485BPOS

As filed with the Securities and Exchange Commission on November 27, 2024

1933 Act Registration No. 333-140895

1940 Act Registration No. 811-22019

United States
Securities and Exchange Commission
Washington, D.C. 20549
  Form N-1A 

Registration Statement Under the Securities Act of 1933	☐
Pre-Effective Amendment No. __	☐
Post-Effective Amendment No. 46	☒
and
Registration Statement Under the Investment Company Act of 1940	☐
Amendment No. 49	☒

First Trust Exchange-Traded AlphaDEX ® Fund
(Exact Name of Registrant as Specified in Charter)
120 East Liberty Drive, Suite 400
Wheaton, Illinois 60187
(Address of Principal Executive Offices) (Zip Code)

Registrant’s Telephone Number, Including Area Code: (800) 621-1675

W. Scott Jardine, Esq., Secretary
First Trust Exchange-Traded AlphaDEX® Fund
First Trust Advisors L.P.
120 East Liberty Drive, Suite 400
Wheaton, Illinois 60187
(Name and Address of Agent for Service)

Copy to:
Eric F. Fess, Esq.
Chapman and Cutler LLP
320 South Canal Street
Chicago, Illinois 60606

It is proposed that this filing will become effective (check appropriate box): 

☐	immediately upon filing pursuant to paragraph (b)
☒	on December 2, 2024 pursuant to paragraph (b)
☐	60 days after filing pursuant to paragraph (a)(1)
☐	on (date) pursuant to paragraph (a)(1)
☐	75 days after filing pursuant to paragraph (a)(2)
☐	on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box: 

☐ this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

Contents of Post-Effective Amendment No. 46

This Registration Statement comprises the following papers and contents:

The Facing Sheet

Part A - Prospectus for First Trust Consumer Discretionary AlphaDEX® Fund, First Trust Consumer Staples AlphaDEX® Fund, First Trust Energy AlphaDEX® Fund, First Trust Financials AlphaDEX® Fund, First Trust Health Care AlphaDEX® Fund, First Trust Industrials/Producer Durables AlphaDEX® Fund, First Trust Materials AlphaDEX® Fund, First Trust Technology AlphaDEX® Fund, First Trust Utilities AlphaDEX® Fund, First Trust Large Cap Core AlphaDEX® Fund, First Trust Large Cap Growth AlphaDEX® Fund, First Trust Large Cap Value AlphaDEX® Fund, First Trust Mid Cap Core AlphaDEX® Fund, First Trust Mid Cap Growth AlphaDEX® Fund, First Trust Mid Cap Value AlphaDEX® Fund, First Trust Multi Cap Growth AlphaDEX® Fund, First Trust Multi Cap Value AlphaDEX® Fund, First Trust Small Cap Core AlphaDEX® Fund, First Trust Small Cap Growth AlphaDEX® Fund and First Trust Small Cap Value AlphaDEX® Fund

Part B - Statement of Additional Information for First Trust Consumer Discretionary AlphaDEX® Fund, First Trust Consumer Staples AlphaDEX® Fund, First Trust Energy AlphaDEX® Fund, First Trust Financials AlphaDEX® Fund, First Trust Health Care AlphaDEX® Fund, First Trust Industrials/Producer Durables AlphaDEX® Fund, First Trust Materials AlphaDEX® Fund, First Trust Technology AlphaDEX® Fund, First Trust Utilities AlphaDEX® Fund, First Trust Large Cap Core AlphaDEX® Fund, First Trust Large Cap Growth AlphaDEX® Fund, First Trust Large Cap Value AlphaDEX® Fund, First Trust Mid Cap Core AlphaDEX® Fund, First Trust Mid Cap Growth AlphaDEX® Fund, First Trust Mid Cap Value AlphaDEX® Fund, First Trust Multi Cap Growth AlphaDEX® Fund, First Trust Multi Cap Value AlphaDEX® Fund, First Trust Small Cap Core AlphaDEX® Fund, First Trust Small Cap Growth AlphaDEX® Fund and First Trust Small Cap Value AlphaDEX® Fund

Part C - Other Information

Signatures

Index to Exhibits

Exhibits

 

First Trust

Exchange-Traded AlphaDEX® Fund

 

Prospectus 

FUND NAME	TICKER SYMBOL	EXCHANGE
ALPHADEX® SECTOR FUNDS
First Trust Consumer Discretionary AlphaDEX® Fund	FXD	NYSE Arca
First Trust Consumer Staples AlphaDEX® Fund	FXG	NYSE Arca
First Trust Energy AlphaDEX® Fund	FXN	NYSE Arca
First Trust Financials AlphaDEX® Fund	FXO	NYSE Arca
First Trust Health Care AlphaDEX® Fund	FXH	NYSE Arca
First Trust Industrials/Producer Durables AlphaDEX® Fund	FXR	NYSE Arca
First Trust Materials AlphaDEX® Fund	FXZ	NYSE Arca
First Trust Technology AlphaDEX® Fund	FXL	NYSE Arca
First Trust Utilities AlphaDEX® Fund	FXU	NYSE Arca
ALPHADEX® STYLE FUNDS
First Trust Large Cap Core AlphaDEX® Fund	FEX	Nasdaq
First Trust Large Cap Growth AlphaDEX® Fund	FTC	Nasdaq
First Trust Large Cap Value AlphaDEX® Fund	FTA	Nasdaq
First Trust Mid Cap Core AlphaDEX® Fund	FNX	Nasdaq
First Trust Mid Cap Growth AlphaDEX® Fund	FNY	Nasdaq
First Trust Mid Cap Value AlphaDEX® Fund	FNK	Nasdaq
First Trust Multi Cap Growth AlphaDEX® Fund	FAD	Nasdaq
First Trust Multi Cap Value AlphaDEX® Fund	FAB	Nasdaq
First Trust Small Cap Core AlphaDEX® Fund	FYX	Nasdaq
First Trust Small Cap Growth AlphaDEX® Fund	FYC	Nasdaq
First Trust Small Cap Value AlphaDEX® Fund	FYT	Nasdaq

Each of the funds listed above under AlphaDEX® Sector Funds (each a “Fund,” and collectively, the “AlphaDEX® Sector Funds”) lists and principally trades its shares on NYSE Arca, Inc. (“NYSE Arca” or an “Exchange”). Each of the funds listed above under AlphaDEX® Style Funds (each a “Fund,” and collectively, the “AlphaDEX® Style Funds”) lists and principally trades its shares on Nasdaq, Inc. (“Nasdaq” or an “Exchange”). Market prices may differ to some degree from the net asset value of the shares. Unlike mutual funds, each Fund issues and redeems shares at net asset value, only in large blocks of shares called “Creation Units.”

Each Fund is a series of First Trust Exchange-Traded AlphaDEX® Fund (the “Trust”) and an exchange-traded index fund organized as a separate series of a registered management investment company.

Except when aggregated in Creation Units, the shares are not redeemable securities of the Funds.

The Securities and Exchange Commission has not approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

NOT FDIC INSURED MAY LOSE VALUE NO BANK GUARANTEE

December 2, 2024

 

Table of Contents 

Summary Information
AlphaDEX® Sector Funds
First Trust Consumer Discretionary AlphaDEX® Fund (FXD)	3
First Trust Consumer Staples AlphaDEX® Fund (FXG)	11
First Trust Energy AlphaDEX® Fund (FXN)	19
First Trust Financials AlphaDEX® Fund (FXO)	27
First Trust Health Care AlphaDEX® Fund (FXH)	35
First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)	43
First Trust Materials AlphaDEX® Fund (FXZ)	51
First Trust Technology AlphaDEX® Fund (FXL)	59
First Trust Utilities AlphaDEX® Fund (FXU)	67
AlphaDEX® Style Funds
First Trust Large Cap Core AlphaDEX® Fund (FEX)	75
First Trust Large Cap Growth AlphaDEX® Fund (FTC)	83
First Trust Large Cap Value AlphaDEX® Fund (FTA)	91
First Trust Mid Cap Core AlphaDEX® Fund (FNX)	99
First Trust Mid Cap Growth AlphaDEX® Fund (FNY)	107
First Trust Mid Cap Value AlphaDEX® Fund (FNK)	115
First Trust Multi Cap Growth AlphaDEX® Fund (FAD)	123
First Trust Multi Cap Value AlphaDEX® Fund (FAB)	131
First Trust Small Cap Core AlphaDEX® Fund (FYX)	139
First Trust Small Cap Growth AlphaDEX® Fund (FYC)	147
First Trust Small Cap Value AlphaDEX® Fund (FYT)	155
Additional Information on the Funds' Investment Objectives and Strategies	163
Fund Investments	166
Risks of Investing in the Funds	167
Fund Organization	176
Management of the Funds	176
How to Buy and Sell Shares	178
Dividends, Distributions and Taxes	179
Federal Tax Matters	179
Distribution Plan	182
Net Asset Value	182
Fund Service Providers	183
Index Providers	183
Disclaimers	183
Premium/Discount Information	185
Financial Highlights	186
Other Information	206

Summary Information First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

Investment Objective

The First Trust Consumer Discretionary AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Consumer Discretionary Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.11%
Total Annual Fund Operating Expenses	0.61%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.61%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$62	$195	$340	$762

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 84% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the

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First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the consumer discretionary sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 121 securities with a market capitalization range of $1.97 billion to $1.96 trillion. As of October 31, 2024, the Fund had significant investments in consumer discretionary companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CONSUMER DISCRETIONARY COMPANIES RISK. Consumer discretionary companies, such as retailers, media companies and consumer services companies, provide non-essential goods and services. These companies manufacture products and provide discretionary services directly to the consumer, and the success of these companies is tied closely to the performance of the overall domestic and international economy, interest rates, competition and consumer confidence. Success depends

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First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

heavily on disposable household income and consumer spending. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer discretionary products in the marketplace.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended

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First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce

6

First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

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First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Consumer Discretionary Index (formerly the Russell 1000® Consumer Discretionary and Services Index), on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Consumer Discretionary Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Consumer Discretionary AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.06%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	38.85%	June 30, 2020
Worst Quarter	-40.28%	March 31, 2020
Year-to-Date	8.06%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

8

First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	23.28%	10.73%	7.14%	7.56%	5/8/2007
Return After Taxes on Distributions	22.90%	10.36%	6.76%	7.22%
Return After Taxes on Distributions and Sale of Fund Shares	13.76%	8.34%	5.57%	6.15%
StrataQuant® Consumer Discretionary Index (reflects no deduction for fees, expenses or taxes)	24.08%	11.42%	7.82%	8.30%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Consumer Discretionary Index (reflects no deduction for fees, expenses or taxes)	42.41%	13.73%	11.69%	11.08%
Russell 1000® Consumer Discretionary Index(1) (reflects no deduction for fees, expenses or taxes)	36.88%	14.10%	11.50%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

9

First Trust Consumer Discretionary AlphaDEX® Fund (FXD)

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

10

Summary Information First Trust Consumer Staples AlphaDEX® Fund (FXG)

Investment Objective

The First Trust Consumer Staples AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Consumer Staples Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.12%
Total Annual Fund Operating Expenses	0.62%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.62%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$63	$199	$346	$774

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 67% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the

11

First Trust Consumer Staples AlphaDEX® Fund (FXG)

right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the consumer staples sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $1.4 billion to $281.34 billion. As of October 31, 2024, the Fund had significant investments in consumer staples companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CONSUMER STAPLES COMPANIES RISK. Consumer staples companies provide products directly to the consumer that are typically considered non-discretionary items based on consumer purchasing habits. Such products include food, beverages, household items and tobacco. Companies providing these products may be affected by the regulation of various product components and production methods, new laws, regulations or litigation, marketing campaigns, competitive pricing and other factors affecting consumer demand. Changes in the worldwide economy, demographics, consumer preferences, consumer

12

First Trust Consumer Staples AlphaDEX® Fund (FXG)

spending, exploration and production spending may adversely affect these companies, as well as natural and man-made disasters, political, social or labor unrest, world events and economic conditions.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended

13

First Trust Consumer Staples AlphaDEX® Fund (FXG)

periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce

14

First Trust Consumer Staples AlphaDEX® Fund (FXG)

their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

15

First Trust Consumer Staples AlphaDEX® Fund (FXG)

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Consumer Staples Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Consumer Staples Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Consumer Staples AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.53%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	15.54%	June 30, 2020
Worst Quarter	-19.62%	March 31, 2020
Year-to-Date	9.53%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

16

First Trust Consumer Staples AlphaDEX® Fund (FXG)

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	1.92%	10.13%	7.61%	8.73%	5/8/2007
Return After Taxes on Distributions	1.33%	9.41%	6.88%	8.09%
Return After Taxes on Distributions and Sale of Fund Shares	1.13%	7.68%	5.78%	7.03%
StrataQuant® Consumer Staples Index (reflects no deduction for fees, expenses or taxes)	2.50%	10.79%	8.28%	9.48%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Consumer Staples Index (reflects no deduction for fees, expenses or taxes)	0.52%	10.86%	8.54%	9.23%
Russell 1000® Consumer Staples Index(1) (reflects no deduction for fees, expenses or taxes)	-2.59%	9.65%	7.70%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

17

First Trust Consumer Staples AlphaDEX® Fund (FXG)

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

18

Summary Information First Trust Energy AlphaDEX® Fund (FXN)

Investment Objective

The First Trust Energy AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Energy Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.11%
Total Annual Fund Operating Expenses	0.61%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.61%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$62	$195	$340	$762

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 60% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing

19

First Trust Energy AlphaDEX® Fund (FXN)

one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the energy sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $2.11 billion to $518.83 billion. As of October 31, 2024, the Fund had significant investments in energy companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in

20

First Trust Energy AlphaDEX® Fund (FXN)

disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

ENERGY COMPANIES RISK. The success of energy companies may be cyclical and highly dependent on energy prices. The market value of securities issued by energy companies may decline for many reasons, including, among other things, changes in the levels and volatility of global energy prices, energy supply and demand, capital expenditures on exploration and production of energy sources, exchange rates, interest rates, economic conditions, tax treatment, energy conservation efforts, increased competition and technological advances. Energy companies may be subject to substantial government regulation and contractual fixed pricing, which may increase the cost of doing business and limit the earnings of these companies. A significant portion of the revenues of energy companies may depend on a relatively small number of customers, including governmental entities and utilities. As a result, governmental budget constraints may have a material adverse effect on the stock prices of energy companies. Energy companies may also operate in, or engage in transactions involving, countries with less developed regulatory regimes or a history of expropriation, nationalization or other adverse policies. Energy companies also face a significant risk of liability from accidents resulting in injury or loss of life or property, pollution or other environmental problems, equipment malfunctions or mishandling of materials and a risk of loss from terrorism, political strife or natural disasters.

21

First Trust Energy AlphaDEX® Fund (FXN)

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected

22

First Trust Energy AlphaDEX® Fund (FXN)

under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large

23

First Trust Energy AlphaDEX® Fund (FXN)

discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Energy Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. In addition to the implementation of the RGS, Russell combined the Russell 1000® Integrated Oils Index and the Russell 1000® Other Energy Index into one index, the Russell 1000® Energy Index. Consequently, performance data is not available for all the periods shown in the table for the Russell 1000® Energy Index because this index did not exist until on or about September 18, 2008.

First Trust Energy AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was -1.02%.

24

First Trust Energy AlphaDEX® Fund (FXN)

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	65.48%	June 30, 2020
Worst Quarter	-61.97%	March 31, 2020
Year-to-Date	-1.02%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	0.78%	10.86%	-1.98%	0.44%	5/8/2007
Return After Taxes on Distributions	-0.52%	9.56%	-2.84%	-0.18%
Return After Taxes on Distributions and Sale of Fund Shares	0.42%	7.87%	-1.90%	0.03%
StrataQuant® Energy Index (reflects no deduction for fees, expenses or taxes)	1.51%	11.59%	-1.42%	1.07%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Energy Index (reflects no deduction for fees, expenses or taxes)	-1.33%	13.40%	3.48%	4.58%
Russell 1000® Energy Index(1) (reflects no deduction for fees, expenses or taxes)	-2.33%	12.87%	2.81%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

25

First Trust Energy AlphaDEX® Fund (FXN)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

26

Summary Information First Trust Financials AlphaDEX® Fund (FXO)

Investment Objective

The First Trust Financials AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Financials Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.11%
Total Annual Fund Operating Expenses	0.61%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.61%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$62	$195	$340	$762

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 75% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing

27

First Trust Financials AlphaDEX® Fund (FXO)

one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the financials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 103 securities with a market capitalization range of $647.99 million to $972.07 billion. As of October 31, 2024, the Fund had significant investments in financial companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in

28

First Trust Financials AlphaDEX® Fund (FXO)

disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.

29

First Trust Financials AlphaDEX® Fund (FXO)

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares.

30

First Trust Financials AlphaDEX® Fund (FXO)

Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial

31

First Trust Financials AlphaDEX® Fund (FXO)

resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Financial Services Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Financial Services Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Financials AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 19.89%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	36.00%	December 31, 2020
Worst Quarter	-36.22%	March 31, 2020
Year-to-Date	19.89%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and,

32

First Trust Financials AlphaDEX® Fund (FXO)

therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	9.22%	12.79%	9.48%	6.85%	5/8/2007
Return After Taxes on Distributions	7.77%	11.60%	8.50%	6.02%
Return After Taxes on Distributions and Sale of Fund Shares	5.36%	9.60%	7.22%	5.19%
StrataQuant® Financials Index (reflects no deduction for fees, expenses or taxes)	9.90%	13.55%	10.21%	7.68%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Financials Index (reflects no deduction for fees, expenses or taxes)	12.15%	11.97%	10.05%	3.42%
Russell 1000® Financials Index(1) (reflects no deduction for fees, expenses or taxes)	15.46%	14.78%	11.59%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An

33

First Trust Financials AlphaDEX® Fund (FXO)

investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

34

Summary Information First Trust Health Care AlphaDEX® Fund (FXH)

Investment Objective

The First Trust Health Care AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Health Care Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.10%
Total Annual Fund Operating Expenses	0.60%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.60%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$61	$192	$335	$750

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 98% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing

35

First Trust Health Care AlphaDEX® Fund (FXH)

one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the health care sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 78 securities with a market capitalization range of $1.94 billion to $746.2 billion. As of October 31, 2024, the Fund had significant investments in health care companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in

36

First Trust Health Care AlphaDEX® Fund (FXH)

disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

HEALTH CARE COMPANIES RISK. Health care companies, such as companies providing medical and healthcare goods and services, companies engaged in manufacturing medical equipment, supplies and pharmaceuticals, as well as operating health

37

First Trust Health Care AlphaDEX® Fund (FXH)

care facilities and the provision of managed health care, may be affected by government regulations and government health care programs, increases or decreases in the cost of medical products and services and product liability claims, among other factors. Many health care companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Health care companies are also subject to competitive forces that may result in price discounting, may be thinly capitalized and susceptible to product obsolescence.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price.

38

First Trust Health Care AlphaDEX® Fund (FXH)

The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial

39

First Trust Health Care AlphaDEX® Fund (FXH)

resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Health Care Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Health Care Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Health Care AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.40%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	22.21%	June 30, 2020
Worst Quarter	-19.65%	December 31, 2018
Year-to-Date	8.40%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and,

40

First Trust Health Care AlphaDEX® Fund (FXH)

therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	-4.50%	8.59%	8.02%	10.46%	5/8/2007
Return After Taxes on Distributions	-4.60%	8.55%	8.00%	10.43%
Return After Taxes on Distributions and Sale of Fund Shares	-2.67%	6.77%	6.54%	9.03%
StrataQuant® Health Care Index (reflects no deduction for fees, expenses or taxes)	-3.88%	9.32%	8.73%	11.23%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Health Care Index (reflects no deduction for fees, expenses or taxes)	2.06%	11.59%	11.35%	10.28%
Russell 1000® Health Care Index(1) (reflects no deduction for fees, expenses or taxes)	2.44%	11.51%	11.37%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An

41

First Trust Health Care AlphaDEX® Fund (FXH)

investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

42

Summary Information First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

Investment Objective

The First Trust Industrials/Producer Durables AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Industrials Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.10%
Total Annual Fund Operating Expenses	0.60%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.60%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$61	$192	$335	$750

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 78% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the

43

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the industrials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 138 securities with a market capitalization range of $1.78 billion to $190.26 billion. As of October 31, 2024, the Fund had significant investments in industrials companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to

44

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

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First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.

46

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

47

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Producer Durables Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Producer Durables Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Industrials/Producer Durables AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 17.53%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	24.70%	June 30, 2020
Worst Quarter	-32.06%	March 31, 2020
Year-to-Date	17.53%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

48

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	26.80%	14.74%	9.55%	8.21%	5/8/2007
Return After Taxes on Distributions	26.37%	14.32%	9.16%	7.86%
Return After Taxes on Distributions and Sale of Fund Shares	15.85%	11.65%	7.63%	6.73%
StrataQuant® Industrials Index (reflects no deduction for fees, expenses or taxes)	27.67%	15.53%	10.29%	8.98%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Industrials Index (reflects no deduction for fees, expenses or taxes)	18.13%	14.21%	10.00%	8.69%
Russell 1000® Industrials Index(1) (reflects no deduction for fees, expenses or taxes)	20.35%	12.16%	9.34%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

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First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

50

Summary Information First Trust Materials AlphaDEX® Fund (FXZ)

Investment Objective

The First Trust Materials AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Materials Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.11%
Total Annual Fund Operating Expenses	0.61%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.61%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$62	$195	$340	$762

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing

51

First Trust Materials AlphaDEX® Fund (FXZ)

one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the materials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 36 securities with a market capitalization range of $2.71 billion to $217.81 billion. As of October 31, 2024, the Fund had significant investments in materials companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024.To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in

52

First Trust Materials AlphaDEX® Fund (FXZ)

disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or

53

First Trust Materials AlphaDEX® Fund (FXZ)

the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market

54

First Trust Materials AlphaDEX® Fund (FXZ)

developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

MATERIALS COMPANIES RISK. Materials and processing companies are involved in the extraction or processing of raw materials such as metals, ore and forestry products. These companies are sensitive to changes in the business cycle and fluctuations in the supply and demand for raw materials. Further, certain materials and processing companies can be affected by shifts in the housing market, as many produced raw materials are components of construction projects. Rising wage costs can also impact companies that rely on skilled labor. In addition, materials and processing companies may be significantly affected by volatility of commodity prices, import controls, worldwide competition, liability for environmental damage, depletion of resources and mandated expenditures for safety and pollution control devices.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial

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First Trust Materials AlphaDEX® Fund (FXZ)

resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Materials and Processing Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Materials and Processing Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Materials AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was -1.82%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	28.72%	December 31, 2020
Worst Quarter	-31.31%	March 31, 2020
Year-to-Date	-1.82%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and,

56

First Trust Materials AlphaDEX® Fund (FXZ)

therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	16.10%	17.49%	9.48%	9.30%	5/8/2007
Return After Taxes on Distributions	15.12%	16.68%	8.80%	8.67%
Return After Taxes on Distributions and Sale of Fund Shares	9.50%	13.75%	7.38%	7.52%
StrataQuant® Materials Index (reflects no deduction for fees, expenses or taxes)	16.80%	18.31%	10.22%	10.09%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Materials Index (reflects no deduction for fees, expenses or taxes)	12.55%	13.58%	8.60%	7.11%
Russell 1000® Basic Materials Index(1) (reflects no deduction for fees, expenses or taxes)	13.35%	14.02%	8.86%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An

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First Trust Materials AlphaDEX® Fund (FXZ)

investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

58

Summary Information First Trust Technology AlphaDEX® Fund (FXL)

Investment Objective

The First Trust Technology AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Technology Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.10%
Total Annual Fund Operating Expenses	0.60%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.60%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$61	$192	$335	$750

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 119% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the

59

First Trust Technology AlphaDEX® Fund (FXL)

right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the technology sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 103 securities with a market capitalization range of $2.7 billion to $3.43 trillion. As of October 31, 2024, the Fund had significant investments in information technology companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to

60

First Trust Technology AlphaDEX® Fund (FXL)

achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

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First Trust Technology AlphaDEX® Fund (FXL)

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INFORMATION TECHNOLOGY COMPANIES RISK. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.

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First Trust Technology AlphaDEX® Fund (FXL)

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

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First Trust Technology AlphaDEX® Fund (FXL)

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Technology Index , on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Technology Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Technology AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.19%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	40.67%	June 30, 2020
Worst Quarter	-18.87%	June 30, 2022
Year-to-Date	8.19%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

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First Trust Technology AlphaDEX® Fund (FXL)

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	40.43%	19.84%	16.17%	12.13%	5/8/2007
Return After Taxes on Distributions	40.19%	19.71%	15.97%	11.99%
Return After Taxes on Distributions and Sale of Fund Shares	23.93%	16.16%	13.67%	10.51%
StrataQuant® Technology Index (reflects no deduction for fees, expenses or taxes)	40.85%	20.55%	16.82%	12.89%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Information Technology Index (reflects no deduction for fees, expenses or taxes)	57.84%	26.95%	20.79%	15.48%
Russell 1000® Technology Index(1) (reflects no deduction for fees, expenses or taxes)	66.89%	26.45%	20.26%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

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First Trust Technology AlphaDEX® Fund (FXL)

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Utilities AlphaDEX® Fund (FXU)

Investment Objective

The First Trust Utilities AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Utilities Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.13%
Total Annual Fund Operating Expenses	0.63%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.63%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$64	$202	$351	$787

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing

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First Trust Utilities AlphaDEX® Fund (FXU)

one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index.

According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the utilities sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens.

2.

The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores.

3.

The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2.

4.

The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $3.27 billion to $162.97 billion. As of October 31, 2024, the Fund had significant investments in utilities companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in

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First Trust Utilities AlphaDEX® Fund (FXU)

disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or

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First Trust Utilities AlphaDEX® Fund (FXU)

the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market

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First Trust Utilities AlphaDEX® Fund (FXU)

developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will

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First Trust Utilities AlphaDEX® Fund (FXU)

remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

UTILITY COMPANIES RISK. Utility companies include companies producing or providing gas, electricity or water. These companies are subject to the risk of the imposition of rate caps, increased competition due to deregulation, the difficulty in obtaining an adequate return on invested capital or in financing large construction projects counterparty risk, the limitations on operations and increased costs and delays attributable to environmental considerations and the capital market’s ability to absorb utility debt. In addition, taxes, government regulation, domestic and international politics, price and supply fluctuations, volatile interest rates and energy conservation may negatively affect utility companies.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

With respect to the Russell 1000® Utilities Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Utilities Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.

First Trust Utilities AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 23.75%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	16.49%	March 31, 2016
Worst Quarter	-15.50%	March 31, 2020
Year-to-Date	23.75%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and,

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First Trust Utilities AlphaDEX® Fund (FXU)

therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	-2.20%	6.19%	7.55%	5.91%	5/8/2007
Return After Taxes on Distributions	-3.22%	5.04%	6.29%	4.67%
Return After Taxes on Distributions and Sale of Fund Shares	-1.32%	4.29%	5.43%	4.13%
StrataQuant® Utilities Index (reflects no deduction for fees, expenses or taxes)	-1.54%	6.85%	8.27%	6.72%
Russell 1000® Index (reflects no deduction for fees, expenses or taxes)	26.53%	15.52%	11.80%	9.31%
S&P 500® Utilities Index (reflects no deduction for fees, expenses or taxes)	-7.08%	7.11%	8.91%	6.35%
Russell 1000® Utilities Index(1) (reflects no deduction for fees, expenses or taxes)	-4.66%	7.49%	7.67%	N/A
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An

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First Trust Utilities AlphaDEX® Fund (FXU)

investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

74

Summary Information First Trust Large Cap Core AlphaDEX® Fund (FEX)

Investment Objective

The First Trust Large Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap CoreTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.58%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.58%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$59	$186	$324	$726

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 88% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the 500 largest securities from the Nasdaq US BenchmarkTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 375 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 375 securities with a market capitalization range of $10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares.

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index and a broad-based market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Core Index to the Nasdaq AlphaDEX Large Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Core Index.

First Trust Large Cap Core AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 16.48%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	25.33%	June 30, 2020
Worst Quarter	-26.64%	March 31, 2020
Year-to-Date	16.48%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	14.40%	13.12%	9.60%	8.18%	5/8/2007
Return After Taxes on Distributions	13.72%	12.49%	9.00%	7.64%
Return After Taxes on Distributions and Sale of Fund Shares	8.50%	10.18%	7.55%	6.58%
Nasdaq AlphaDEX Large Cap CoreTM Index(1) (reflects no deduction for fees, expenses or taxes)	15.12%	13.82%	N/A	N/A
Nasdaq US 500 Large CapTM Index(1) (reflects no deduction for fees, expenses or taxes)	27.14%	15.74%	N/A	N/A
S&P 500® Index (reflects no deduction for fees, expenses or taxes)	26.29%	15.69%	12.03%	9.33%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

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First Trust Large Cap Core AlphaDEX® Fund (FEX)

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

82

Summary Information First Trust Large Cap Growth AlphaDEX® Fund (FTC)

Investment Objective

The First Trust Large Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap GrowthTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.58%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.58%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$59	$186	$324	$726

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 116% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 500 Large CapTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 187 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 187 securities with a market capitalization range of $10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrials companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.

LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Growth Index to the Nasdaq AlphaDEX Large Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Growth Index.

First Trust Large Cap Growth AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 20.10%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	28.17%	June 30, 2020
Worst Quarter	-18.53%	December 31, 2018
Year-to-Date	20.10%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	20.12%	14.48%	10.98%	8.74%	5/8/2007
Return After Taxes on Distributions	19.77%	14.21%	10.70%	8.48%
Return After Taxes on Distributions and Sale of Fund Shares	11.89%	11.51%	8.96%	7.27%
Nasdaq AlphaDEX Large Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	20.90%	15.19%	N/A	N/A
Nasdaq US 500 Large Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	31.58%	17.47%	N/A	N/A
S&P 500® Index (reflects no deduction for fees, expenses or taxes)	26.29%	15.69%	12.03%	9.33%
S&P 500® Growth Index (reflects no deduction for fees, expenses or taxes)	30.03%	16.23%	13.35%	10.95%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since

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First Trust Large Cap Growth AlphaDEX® Fund (FTC)

shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Large Cap Value AlphaDEX® Fund (FTA)

Investment Objective

The First Trust Large Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap ValueTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.58%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.58%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$59	$186	$324	$726

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 81% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 500 Large CapTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 187 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 187 securities with a market capitalization range of $10.68 billion to $518.83 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

93

First Trust Large Cap Value AlphaDEX® Fund (FTA)

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Value Index to the Nasdaq AlphaDEX Large Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Value Index.

First Trust Large Cap Value AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 13.21%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	23.83%	June 30, 2020
Worst Quarter	-34.34%	March 31, 2020
Year-to-Date	13.21%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	10.14%	11.20%	7.94%	7.27%	5/8/2007
Return After Taxes on Distributions	9.16%	10.27%	7.06%	6.48%
Return After Taxes on Distributions and Sale of Fund Shares	5.97%	8.44%	5.95%	5.59%
Nasdaq AlphaDEX Large Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	10.86%	11.91%	N/A	N/A
Nasdaq US 500 Large Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	20.36%	13.66%	N/A	N/A
S&P 500® Index (reflects no deduction for fees, expenses or taxes)	26.29%	15.69%	12.03%	9.33%
S&P 500® Value Index (reflects no deduction for fees, expenses or taxes)	22.23%	14.11%	10.01%	7.29%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums

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First Trust Large Cap Value AlphaDEX® Fund (FTA)

and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Mid Cap Core AlphaDEX® Fund (FNX)

Investment Objective

The First Trust Mid Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap CoreTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.08%
Total Annual Fund Operating Expenses	0.58%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.58%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$59	$186	$324	$726

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 103% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the securities that are ranked 501 to 1100 by full company market capitalization from the Nasdaq US BenchmarkTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 450 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 450 securities with a market capitalization range of $2.11 billion to $27.07 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no

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assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Core Index to the Nasdaq AlphaDEX Mid Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Core Index.

First Trust Mid Cap Core AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 13.09%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	29.56%	June 30, 2020
Worst Quarter	-33.06%	March 31, 2020
Year-to-Date	13.09%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	20.43%	13.86%	8.70%	8.77%	5/8/2007
Return After Taxes on Distributions	19.84%	13.31%	8.22%	8.37%
Return After Taxes on Distributions and Sale of Fund Shares	12.06%	10.84%	6.84%	7.21%
Nasdaq AlphaDEX Mid Cap CoreTM Index(1) (reflects no deduction for fees, expenses or taxes)	21.22%	14.60%	N/A	N/A
Nasdaq US 600 Mid CapTM Index(1) (reflects no deduction for fees, expenses or taxes)	19.07%	11.81%	N/A	N/A
S&P MidCap 400® Index (reflects no deduction for fees, expenses or taxes)	16.44%	12.62%	9.27%	8.74%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

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First Trust Mid Cap Core AlphaDEX® Fund (FNX)

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

Investment Objective

The First Trust Mid Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap GrowthTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.70%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.00%
Total Annual Fund Operating Expenses	0.70%

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$72	$224	$390	$871

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 134% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 600 Mid CapTM Index.

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 225 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 225 securities with a market capitalization range of $2.69 billion to $27.07 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Growth Index to the Nasdaq AlphaDEX Mid Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Growth Index.

First Trust Mid Cap Growth AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 17.44%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	29.17%	June 30, 2020
Worst Quarter	-22.72%	March 31, 2020
Year-to-Date	17.44%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	21.06%	13.67%	9.56%	10.35%	4/19/2011
Return After Taxes on Distributions	20.93%	13.57%	9.44%	10.23%
Return After Taxes on Distributions and Sale of Fund Shares	12.46%	10.93%	7.81%	8.66%
Nasdaq AlphaDEX Mid Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	21.93%	14.52%	N/A	N/A
Nasdaq US 600 Mid Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	20.09%	11.04%	N/A	N/A
S&P MidCap 400® Growth Index (reflects no deduction for fees, expenses or taxes)	17.49%	11.91%	9.04%	10.08%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	12.41%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums

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First Trust Mid Cap Growth AlphaDEX® Fund (FNY)

and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Mid Cap Value AlphaDEX® Fund (FNK)

Investment Objective

The First Trust Mid Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap ValueTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.70%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.00%
Total Annual Fund Operating Expenses	0.70%

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$72	$224	$390	$871

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 98% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 600 Mid CapTM Index.

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 225 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 225 securities with a market capitalization range of $2.11 billion to $19.57 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Value Index to the Nasdaq AlphaDEX Mid Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Value Index.

First Trust Mid Cap Value AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.14%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	31.25%	June 30, 2020
Worst Quarter	-41.22%	March 31, 2020
Year-to-Date	8.14%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	20.64%	12.78%	7.26%	9.17%	4/19/2011
Return After Taxes on Distributions	19.71%	11.98%	6.56%	8.53%
Return After Taxes on Distributions and Sale of Fund Shares	12.17%	9.80%	5.47%	7.27%
Nasdaq AlphaDEX Mid Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	21.64%	13.66%	N/A	N/A
Nasdaq US 600 Mid Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	18.25%	11.50%	N/A	N/A
S&P MidCap 400® Value Index (reflects no deduction for fees, expenses or taxes)	15.39%	12.91%	9.17%	10.36%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	12.41%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

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First Trust Mid Cap Value AlphaDEX® Fund (FNK)

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Summary Information First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

Investment Objective

The First Trust Multi Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Multi Cap GrowthTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.12%
Total Annual Fund Operating Expenses	0.62%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.62%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$63	$199	$346	$774

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 115% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index, Nasdaq US 600 Mid Cap GrowthTM Index and Nasdaq US 700 Small Cap GrowthTM Index (the "Base Indices"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Indices are comprehensive, rules-based indices that include growth securities from the Nasdaq US 500 Large CapTM Index, Nasdaq US 600 Mid CapTM Index, and Nasdaq US 700 Small CapTM Index, respectively.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Indices.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

The following steps are performed for each size-segment independently:

3.

The remaining stocks in each Base Index are then ranked on both growth and value factors within their respective Base Indices. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 187 stocks from the Nasdaq US 500 Large Cap GrowthTM Index, top 225 stocks from the Nasdaq US 600 Mid Cap GrowthTM Index and top 262 stocks from the Nasdaq US 700 Small Cap GrowthTM Index based on the selection score determined in step 3 comprise the “selected stocks.” Within each size-segment, the selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

5.

Using the quintile weights for each size-segment determined in Step 4, security weights are re-scaled such that the sum of large-cap security weights is 50%, the sum of medium-cap security weights is 30%, and the sum of small-cap security weights is 20%.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 674 securities with a market capitalization range of $631.42 million to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrials companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

125

First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.

LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Multi Cap Growth Index to the Nasdaq AlphaDEX Multi Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Multi Cap Growth Index.

First Trust Multi Cap Growth AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 19.19%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	28.87%	June 30, 2020
Worst Quarter	-21.61%	March 31, 2020
Year-to-Date	19.19%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	19.22%	13.43%	10.00%	8.67%	5/8/2007
Return After Taxes on Distributions	18.95%	13.23%	9.81%	8.50%
Return After Taxes on Distributions and Sale of Fund Shares	11.37%	10.67%	8.15%	7.28%
Nasdaq AlphaDEX Multi Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	20.04%	14.21%	N/A	N/A
Nasdaq US Multi Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	30.50%	16.75%	N/A	N/A
S&P Composite 1500® Index (reflects no deduction for fees, expenses or taxes)	29.01%	15.85%	12.97%	10.82%
S&P Composite 1500® Growth Index (reflects no deduction for fees, expenses or taxes)	25.47%	15.39%	11.76%	9.30%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

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First Trust Multi Cap Growth AlphaDEX® Fund (FAD)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

130

Summary Information First Trust Multi Cap Value AlphaDEX® Fund (FAB)

Investment Objective

The First Trust Multi Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Multi Cap ValueTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.14%
Total Annual Fund Operating Expenses	0.64%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.64%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$65	$205	$357	$798

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 87% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index

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First Trust Multi Cap Value AlphaDEX® Fund (FAB)

Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index, Nasdaq US 600 Mid Cap ValueTM Index and Nasdaq US 700 Small Cap ValueTM Index (the "Base Indices"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Indices are comprehensive, rules-based indices that include value securities from the Nasdaq US 500 Large CapTM Index, Nasdaq US 600 Mid CapTM Index, and Nasdaq US 700 Small CapTM Index, respectively.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Indices.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

The following steps are performed for each size-segment independently:

3.

The remaining stocks in each Base Index are then ranked on both growth and value factors within their respective Base Indices. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 187 stocks from the Nasdaq US 500 Large Cap ValueTM Index, top 225 stocks from the Nasdaq US 600 Mid Cap ValueTM Index and top 262 stocks from the Nasdaq US 700 Small Cap ValueTM Index based on the selection score determined in step 3 comprise the “selected stocks.” Within each size-segment, the selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

5.

Using the quintile weights for each size-segment determined in Step 4, security weights are re-scaled such that the sum of large-cap security weights is 50%, the sum of medium-cap security weights is 30%, and the sum of small-cap security weights is 20%.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 674 securities with a market capitalization range of $755.28 million to $518.83 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

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First Trust Multi Cap Value AlphaDEX® Fund (FAB)

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

133

First Trust Multi Cap Value AlphaDEX® Fund (FAB)

FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of

134

First Trust Multi Cap Value AlphaDEX® Fund (FAB)

large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing

135

First Trust Multi Cap Value AlphaDEX® Fund (FAB)

the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Multi Cap Value Index to the Nasdaq AlphaDEX Multi Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Multi Cap Value Index.

First Trust Multi Cap Value AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.69%.

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First Trust Multi Cap Value AlphaDEX® Fund (FAB)

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	28.70%	June 30, 2020
Worst Quarter	-37.95%	March 31, 2020
Year-to-Date	9.69%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	15.80%	12.25%	7.59%	7.58%	5/8/2007
Return After Taxes on Distributions	14.83%	11.42%	6.84%	6.91%
Return After Taxes on Distributions and Sale of Fund Shares	9.31%	9.35%	5.73%	5.95%
Nasdaq AlphaDEX Multi Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	16.65%	13.06%	N/A	N/A
Nasdaq US Multi Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	20.01%	13.52%	N/A	N/A
S&P Composite 1500® Index (reflects no deduction for fees, expenses or taxes)	25.47%	15.39%	11.76%	9.30%
S&P Composite 1500® Value Index (reflects no deduction for fees, expenses or taxes)	21.64%	13.98%	9.91%	7.39%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

137

First Trust Multi Cap Value AlphaDEX® Fund (FAB)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

138

Summary Information First Trust Small Cap Core AlphaDEX® Fund (FYX)

Investment Objective

The First Trust Small Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap CoreTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.50%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.09%
Acquired Fund Fees and Expenses	0.02%
Total Annual Fund Operating Expenses	0.61%
Fee Waiver and Expense Reimbursement(1)	0.00%
Net Annual Fund Operating Expenses	0.61%

(1)

First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$62	$195	$340	$762

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 112% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the

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performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the securities that are ranked 1101 to 1800 by full company market capitalization from the Nasdaq US BenchmarkTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 525 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 525 securities with a market capitalization range of $631.42 million to $11.28 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate

140

First Trust Small Cap Core AlphaDEX® Fund (FYX)

markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant

141

First Trust Small Cap Core AlphaDEX® Fund (FYX)

exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

142

First Trust Small Cap Core AlphaDEX® Fund (FYX)

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no

143

First Trust Small Cap Core AlphaDEX® Fund (FYX)

assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Core Index to the Nasdaq AlphaDEX Small Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Core Index.

First Trust Small Cap Core AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.83%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	33.21%	December 31, 2020
Worst Quarter	-36.40%	March 31, 2020
Year-to-Date	9.83%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

144

First Trust Small Cap Core AlphaDEX® Fund (FYX)

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	18.12%	12.14%	7.51%	7.72%	5/8/2007
Return After Taxes on Distributions	17.48%	11.67%	7.10%	7.40%
Return After Taxes on Distributions and Sale of Fund Shares	10.70%	9.46%	5.87%	6.32%
Nasdaq AlphaDEX Small Cap CoreTM Index(1) (reflects no deduction for fees, expenses or taxes)	18.95%	12.92%	N/A	N/A
Nasdaq US 700 Small CapTM Index(1) (reflects no deduction for fees, expenses or taxes)	18.22%	11.23%	N/A	N/A
S&P SmallCap 600® Index (reflects no deduction for fees, expenses or taxes)	16.05%	11.03%	8.66%	8.42%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	9.15%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums

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and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

146

Summary Information First Trust Small Cap Growth AlphaDEX® Fund (FYC)

Investment Objective

The First Trust Small Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap GrowthTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.70%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.00%
Acquired Fund Fees and Expenses	0.01%
Total Annual Fund Operating Expenses	0.71%

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$73	$227	$395	$883

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 141% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices.

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 700 Small CapTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 262 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 262 securities with a market capitalization range of $631.42 million to $11.28 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in health care companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.

HEALTH CARE COMPANIES RISK. Health care companies, such as companies providing medical and healthcare goods and services, companies engaged in manufacturing medical equipment, supplies and pharmaceuticals, as well as operating health care facilities and the provision of managed health care, may be affected by government regulations and government health care programs, increases or decreases in the cost of medical products and services and product liability claims, among other factors. Many health care companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Health care companies are also subject to competitive forces that may result in price discounting, may be thinly capitalized and susceptible to product obsolescence.

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Growth Index to the Nasdaq AlphaDEX Small Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Growth Index.

First Trust Small Cap Growth AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 18.92%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	30.65%	December 31, 2020
Worst Quarter	-29.82%	March 31, 2020
Year-to-Date	18.92%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	14.15%	9.74%	7.76%	9.65%	4/19/2011
Return After Taxes on Distributions	13.86%	9.59%	7.65%	9.55%
Return After Taxes on Distributions and Sale of Fund Shares	8.37%	7.66%	6.27%	8.05%
Nasdaq AlphaDEX Small Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	15.01%	10.60%	N/A	N/A
Nasdaq US 700 Small Cap GrowthTM Index(1) (reflects no deduction for fees, expenses or taxes)	19.54%	9.86%	N/A	N/A
S&P SmallCap 600® Growth Index (reflects no deduction for fees, expenses or taxes)	17.10%	10.42%	8.96%	10.89%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	12.41%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

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First Trust Small Cap Growth AlphaDEX® Fund (FYC)

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

154

Summary Information First Trust Small Cap Value AlphaDEX® Fund (FYT)

Investment Objective

The First Trust Small Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap ValueTM Index (the “Index”).

Fees and Expenses of the Fund

The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.

Shareholder Fees
(fees paid directly from your investment) 

Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) None

 

Annual Fund Operating Expenses
(expenses that you pay each year as a percentage of the value of your investment) 

Management Fees	0.70%
Distribution and Service (12b-1) Fees	0.00%
Other Expenses	0.00%
Acquired Fund Fees and Expenses	0.02%
Total Annual Fund Operating Expenses	0.72%

Example

The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.

The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be: 

1 Year	3 Years	5 Years	10 Years
$74	$230	$401	$894

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 114% of the average value of its portfolio.

Principal Investment Strategies

The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity.

According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an

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indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 700 Small CapTM Index.

According to the Index Provider, security selection for the Index will be conducted in the following manner:

1.

The selection universe for the Index begins with all stocks in the Base Index.

2.

The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens.

3.

The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.”

4.

The top 262 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.

The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 262 securities with a market capitalization range of $755.28 million to $5.3 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.

Principal Risks

You could lose money by investing in the Fund. An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. There can be no assurance that the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any particular risk factor.

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.

EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.

FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.

INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.

NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.

OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.

TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

Annual Total Return

The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.

On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Value Index to the Nasdaq AlphaDEX Small Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Value Index.

First Trust Small Cap Value AlphaDEX® Fund
Calendar Year Total Returns as of 12/31 (1)

 

(1)

The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 3.23%.

During the periods shown in the chart above: 

	Return	Period Ended
Best Quarter	36.65%	June 30, 2020
Worst Quarter	-41.79%	March 31, 2020
Year-to-Date	3.23%	September 30, 2024

The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.

All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax. Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.

Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

Average Annual Total Returns for the Periods Ended December 31, 2023 

	1 Year	5 Years	10 Years	Since Inception	Inception Date
Return Before Taxes	22.91%	13.45%	6.85%	9.48%	4/19/2011
Return After Taxes on Distributions	22.08%	12.80%	6.29%	8.96%
Return After Taxes on Distributions and Sale of Fund Shares	13.51%	10.44%	5.21%	7.63%
Nasdaq AlphaDEX Small Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	23.96%	14.36%	N/A	N/A
Nasdaq US 700 Small Cap ValueTM Index(1) (reflects no deduction for fees, expenses or taxes)	16.96%	12.27%	N/A	N/A
S&P SmallCap 600® Value Index (reflects no deduction for fees, expenses or taxes)	14.89%	11.31%	8.17%	10.31%
Russell 3000® Index (reflects no deduction for fees, expenses or taxes)	25.96%	15.16%	11.48%	12.41%

(1)

Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

Management

Investment Advisor

First Trust Advisors L.P. (“First Trust” or the “Advisor”)

Portfolio Managers

The Fund’s portfolio is managed by a team (the “Investment Committee”) consisting of:

●

Daniel J. Lindquist, Chairman of the Investment Committee and Managing Director of First Trust

●

David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director of First Trust

●

Jon C. Erickson, Senior Vice President of First Trust

●

Roger F. Testin, Senior Vice President of First Trust

●

Stan Ueland, Senior Vice President of First Trust

●

Chris A. Peterson, Senior Vice President of First Trust

●

Erik Russo, Vice President of First Trust

The Investment Committee members are primarily and jointly responsible for the day-to-day management of the Fund. Each Investment Committee member has served as a part of the portfolio management team of the Fund since 2007, except for Chris A. Peterson and Erik Russo who have served as part of the portfolio management team of the Fund since 2016 and 2020, respectively.

Purchase and Sale of Fund Shares

The Fund issues and redeems shares on a continuous basis, at net asset value, only in large blocks of shares called “Creation Units.” Individual shares of the Fund may only be purchased and sold on the secondary market through a broker-dealer. Since shares of the Fund trade on securities exchanges in the secondary market at their market price rather than their net asset value, the Fund’s shares may trade at a price greater than (premium) or less than (discount) the Fund’s net asset value. An investor may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the Fund (bid) and the lowest price a seller is willing to accept for shares of the Fund (ask) when buying or selling shares in the secondary market (the “bid-ask spread”). Recent information, including the Fund’s net asset value, market price, premiums and discounts, bid-ask spreads and the median bid-ask spread for the Fund’s most recent fiscal year,is available online at http://www.ftportfolios.com/Retail/etf/home.aspx.

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First Trust Small Cap Value AlphaDEX® Fund (FYT)

Tax Information

The Fund’s distributions are taxable and will generally be taxed as ordinary income or capital gains. Distributions on shares held in a tax-deferred account, while not immediately taxable, will be subject to tax when the shares are no longer held in a tax-deferred account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase shares of the Fund through a broker-dealer, registered investment adviser, bank or other financial intermediary (collectively, “intermediaries”), First Trust and First Trust Portfolios L.P., the Fund’s distributor, may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson to recommend the Fund over another investment. Ask your salesperson or visit your financial intermediary’s website for more information.

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Additional Information on the Funds' Investment Objectives and Strategies

Each Fund is a series of First Trust Exchange-Traded AlphaDEX® Fund and is regulated as an “investment company” under the 1940 Act. Each Fund operates as an index fund and is not actively managed by First Trust. As such, each Fund’s investment objective is to provide investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of its Index. In seeking to achieve this objective, each Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise its Index. ICE Data Indices, LLC (“IDI”) serves as the index provider for the indices tracked by the AlphaDEX® Sector Funds and Nasdaq, Inc. serves as the index provider for the indices tracked by the AlphaDEX® Style Funds. IDI is a successor-in-interest to previous entities that maintained the Index in NYSE Group, Inc. and American Stock Exchange LLC. Both IDI and Nasdaq, Inc. may individually be referred to throughout this prospectus as an “Index Provider” and collectively as the “Index Providers.”

Each Fund will generally employ a full replication strategy, meaning that it will normally invest in all of the securities comprising its Index in proportion to their weightings in the Index. However, under various circumstances, full replication of the Index may not be possible or practicable. In those circumstances, a Fund may purchase a sample of securities in its Index. There may also be instances in which First Trust may choose to overweight certain securities in an Index, purchase securities not in an Index which First Trust believes are appropriate to substitute for certain securities in the Index, use futures or derivative instruments or utilize various combinations of the above techniques in seeking to track an Index. Each Fund may sell securities that are represented in its Index in anticipation of their removal from the Index or purchase securities not represented in the Index in anticipation of their addition to the Index.

Each Fund’s investment objective, its 90% investment strategy and each of the policies described herein are non-fundamental policies that may be changed by the Board of Trustees of the Trust (the “Board”) without shareholder approval upon 60 days’ prior written notice to shareholders. Certain fundamental policies of the Funds are set forth in the Statement of Additional Information (“SAI”) in the section entitled “Investment Objective and Policies.”

StrataQuant® Consumer Discretionary Index

The StrataQuant® Consumer Discretionary Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the consumer discretionary sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Consumer Staples Index

The StrataQuant® Consumer Staples Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the consumer staples sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Energy Index

The StrataQuant® Energy Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the energy sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Financials Index

The StrataQuant® Financials Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the financials sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Health Care Index

The StrataQuant® Health Care Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the health care sector from the Russell 1000® Index that have the potential for greater capital appreciation.

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The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Industrials Index

The StrataQuant® Industrials Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the industrials sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Materials Index

The StrataQuant® Materials Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the materials sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Technology Index

The StrataQuant® Technology Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the technology sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

StrataQuant® Utilities Index

The StrataQuant® Utilities Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks comprising the utilities sector from the Russell 1000® Index that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September and December.

Nasdaq AlphaDEX Large Cap CoreTM Index

The Nasdaq AlphaDEX Large Cap CoreTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large CapTM Index. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Large Cap GrowthTM Index

The Nasdaq AlphaDEX Large Cap GrowthTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index classified as "growth stocks" by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Large Cap ValueTM Index

The Nasdaq AlphaDEX Large Cap ValueTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index classified as "value stocks" by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Mid Cap CoreTM Index

The Nasdaq AlphaDEX Mid Cap CoreTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid CapTM Index. The AlphaDEX® security selection methodology aims to select securities

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that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Mid Cap GrowthTM Index

The Nasdaq AlphaDEX Mid Cap GrowthTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap GrowthTM Index classified as “growth stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Mid Cap ValueTM Index

The Nasdaq AlphaDEX Mid Cap ValueTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap ValueTM Index classified as “value stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Multi Cap GrowthTM Index

The Nasdaq AlphaDEX Multi Cap GrowthTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index, the Nasdaq US 600 Mid Cap GrowthTM Index and the Nasdaq US 700 Small Cap GrowthTM Index classified as “growth stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Multi Cap ValueTM Index

The Nasdaq AlphaDEX Multi Cap ValueTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index, the Nasdaq US 600 Mid Cap ValueTM Index and the Nasdaq US 700 Small Cap ValueTM Index classified as “value stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Small Cap CoreTM Index

The Nasdaq AlphaDEX Small Cap CoreTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small CapTM Index. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Small Cap GrowthTM Index

The Nasdaq AlphaDEX Small Cap GrowthTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap GrowthTM Index classified as “growth stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

Nasdaq AlphaDEX Small Cap ValueTM Index

The Nasdaq AlphaDEX Small Cap ValueTM Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap ValueTM Index classified as “value stocks” by the Index Provider. The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional passive-style indices. The Index is rebalanced and reconstituted quarterly as of the last business day of March, June, September, and December.

More information regarding each Index, including additional detail on the Index methodology, may be found on an Index Provider’s website. Neither a Fund, the Board, First Trust, or any of their affiliates, are responsible for the information set forth on an Index Provider’s website. Information from an Index Provider’s website and any other information not expressly included in this prospectus is not incorporated by reference in, and should not be considered part of, this prospectus.

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Fund Investments

Principal Investments

Equity Securities

The Funds invest in common stocks. Common stock represents an equity ownership interest in issuers. Holders of common stock are entitled to the income and increase in the value of the assets and business of the issuers after all debt obligations and obligations to preferred stockholders are satisfied.

Non-Principal Investments

Business Development Companies

Certain Funds may invest in business development companies (“BDCs”). BDCs are a type of closed-end fund regulated under the 1940 Act that typically invest in and lend to small and medium-sized private and certain public companies that may not have access to public equity markets for capital raising. BDCs invest in such diverse industries as healthcare, chemical and manufacturing, technology and service companies. BDCs are unique in that at least 70% of their investments must be made in private and certain public U.S. businesses, and BDCs are required to make available significant managerial assistance to their portfolio companies. Unlike corporations, BDCs are not taxed on income distributed to their shareholders provided they comply with the applicable requirements of the Internal Revenue Code of 1986, as amended. BDCs, which are required to distribute substantially all of their income to investors in order to not be subject to entity level taxation, often offer a yield advantage over other types of securities. A Fund will indirectly bear its proportionate share of any management and other expenses, and of any performance based or incentive fees, charged by the BDCs in which it invests, in addition to the expenses paid by the Fund.

A Fund’s ability to invest in other investment companies, including BDCs, is limited by the 1940 Act and the related rules and interpretations. Each Fund has adopted a policy that it will not invest in other investment companies in excess of 1940 Act limits in reliance on Sections 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act.

Cash Equivalents and Short-Term Investments

Normally, a Fund invests substantially all of its assets to meet its investment objective. Each Fund may invest the remainder of its assets in securities with maturities of less than one year or cash equivalents, or it may hold cash. The percentage of a Fund invested in such holdings varies and depends on several factors, including market conditions. For temporary defensive purposes and during periods of high cash inflows or outflows, a Fund may depart from its principal investment strategies and invest part or all of its assets in these securities, or it may hold cash. During such periods, a Fund may not be able to achieve its investment objective. A Fund may adopt a defensive strategy when the portfolio managers believe securities in which the Fund normally invests have elevated risks due to political or economic factors and in other extraordinary circumstances. For more information on eligible short-term investments, see the SAI.

Real Estate Investment Trusts

Certain Funds may invest in real estate investment trusts ("REITs"). REITs are financial vehicles that pool investors’ capital to purchase or finance real estate. REITs are generally classified as equity REITs, mortgage REITs or a combination of equity and mortgage REITs. Equity REITs invest the majority of their assets directly in real property and derive income primarily from the collection of rents. Equity REITs can also realize capital gains by selling properties that have appreciated in value. Mortgage REITs invest the majority of their assets in real estate mortgages and derive income from the collection of interest payments. REITs are not taxed on income distributed to shareholders provided they comply with the applicable tax requirements.

Illiquid Investments

Certain Funds may invest up to 15% of their net assets in investments and other instruments that are, at the time of investment, illiquid (determined using the Securities and Exchange Commission's standard applicable to investment companies, i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment). For this purpose, illiquid investments may include, but are not limited to, certain restricted securities (securities the disposition of which is restricted under the federal securities laws). Certain securities that may only be sold pursuant to Rule 144A under the Securities Act, that are deemed to be illiquid, and certain repurchase agreements, among others.

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Disclosure of Portfolio Holdings

Each Fund’s portfolio holdings are available on the Funds' website at  http://www.ftportfolios.com.  A description of the policies and procedures with respect to the disclosure of each Fund's portfolio securities is included in the Funds' SAI, which is also available on the Funds' website.

Risks of Investing in the Funds

Risk is inherent in all investing. Investing in a Fund involves risk, including the risk that you may lose all or part of your investment. There can be no assurance that a Fund will meet its stated objectives. Before you invest, you should consider the following disclosure pertaining to the Principal Risks set forth above as well as additional Non-Principal Risks set forth below in this prospectus. The order of the below risk factors does not indicate the significance of any particular risk factor.

Principal Risks

AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with a Fund. A limited number of institutions act as authorized participants for a Fund. Although participants are not obligated to make a market in a Fund’s shares or submit purchase and redemption orders for creation units. To the extent that these institutions exit the business, reduce their role or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, a Fund’s shares may trade at a premium or discount to the Fund’s net asset value and possibly face delisting and the bid/ask spread on the Fund’s shares may widen.

CONSUMER DISCRETIONARY COMPANIES RISK. Certain Funds invest significantly in consumer discretionary companies. Consumer discretionary companies, such as retailers, media companies and consumer services companies, provide non-essential goods and services. These companies manufacture products and provide discretionary services directly to the consumer, and the success of these companies is tied closely to the performance of the overall domestic and international economy, interest rates, competition and consumer confidence. Success depends heavily on disposable household income and consumer spending. Consumer discretionary companies may also be strongly affected by social trends and marketing campaigns. These companies may be subject to severe competition, which may have an adverse impact on their profitability. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer discretionary products in the marketplace. Consumer discretionary companies have historically been characterized as relatively cyclical and therefore more volatile in times of change.

CONSUMER STAPLES COMPANIES RISK. Certain Funds invest significantly in consumer staples companies. Consumer staples companies provide products directly to the consumer that are typically considered non-discretionary items based on consumer purchasing habits. Such products include food, beverages, household items and tobacco. Companies providing these products may be affected by the regulation of various product components and production methods, new laws, regulations or litigation, marketing campaigns, competitive pricing, enumerated factors, consumer confidence, materials costs and other factors affecting consumer demand. Changes in the worldwide economy, demographics, consumer preferences, consumer spending, exploration and production spending may adversely affect these companies, as well as natural and man-made disasters, political, social or labor unrest, world events and economic conditions. Historically, the demand for consumer staples goods has remained fairly constant regardless of the state of the economy. With some products, such as food, alcohol and tobacco, demand sometimes increases during economic downturns. However, price competition among suppliers may be very challenging, which can drive prices lower and impact returns.

CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of a Fund in general, may fall in value due to current market conditions.

As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Funds. While it is hard to predict whether any of these regulations will be adopted, due to the current scope of proposed regulations, any regulatory changes could adversely impact a Fund’s ability to achieve its investment strategies or make certain investments. Regulatory changes may also increase Fund operational costs, which could impact overall performance. Certain market factors may result in central banks changing their approach in the future. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets.

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The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, such as presidential, congressional and gubernatorial elections in the U.S., global elections and governmental changes and the U.S. government’s failure to agree on a long-term budget and deficit reduction plan, have and may continue to have an adverse impact on the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on a Fund’s investments and operations. The potential result of a U.S. federal government shutdown may also significantly impact investor and consumer behavior, which may adversely impact the markets and global economy. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Global and domestic authorities and regulators have previously responded to serious economic disruptions with ranging fiscal and monetary policy changes, including but not limited to, direct capital infusions into companies, new monetary programs and dramatically lower interest rates. Any change in these policies, or the ineffectiveness of these policies, could increase volatility in securities markets, which may adversely impact a Fund’s investments and performance. Any market disruptions could also delay a Fund from making sound investment decisions in a timely manner. If a Fund concentrates its investments in a region enduring geopolitical market disruption, it may face higher risk of loss, although the increasing interconnectivity between global economies and financial markets can lead to events or conditions in one country, region or financial market adversely impacting a different country, region or financial market.

Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of a Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others.

Advancements in technology may also adversely impact markets and the overall performance of a Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. As the use of technology grows, liquidity and market movements may be affected. As artificial intelligence is used more widely, the profitability and growth of Fund holdings may be impacted, which could significantly impact the overall performance of a Fund. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including a Fund, to operate properly.

These events, and any other future events, may adversely affect the prices and liquidity of a Fund’s portfolio investments and could result in disruptions in the trading markets.

CYBER SECURITY RISK. The Funds are susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause a Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause a Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. These risks typically are not covered by insurance. In general, cyber incidents can result from deliberate attacks or unintentional events. Cyber incidents include, but are not limited to, gaining unauthorized access to digital systems (e.g., through “hacking” or malicious software coding) for purposes of misappropriating assets or sensitive information, corrupting data or causing operational disruption. Cyber attacks may also be carried out in a manner that does not require gaining unauthorized access, such as causing denial-of-service attacks on websites (i.e., efforts to make network services unavailable to intended users). Cyber security failures by or breaches of the systems of the Advisor, distributor and other service providers (including, but not limited to, sub-advisors, index providers, fund accountants, custodians, transfer agents and administrators), market makers, authorized participants or the issuers of securities in which a Fund invests, have the ability to cause disruptions and impact business operations, potentially resulting in: financial losses; interference with a Fund’s ability to calculate its net asset value; disclosure of confidential trading

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information; impediments to trading; submission of erroneous trades or erroneous creation or redemption orders; the inability of a Fund or its service providers to transact business; violations of applicable privacy and other laws; regulatory fines penalties, reputational damage, reimbursement or other compensation costs; or additional compliance costs. Substantial costs may be incurred by a Fund in order to resolve or prevent cyber incidents in the future. While the Funds have established business continuity plans in the event of, and risk management systems to prevent, such cyber attacks, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified and that prevention and remediation efforts will not be successful. Furthermore, the Funds cannot control the cyber security plans and systems put in place by service providers to the Funds, issuers in which the Funds invest, market makers or authorized participants. However, there is no guarantee that such efforts will succeed, and the Funds and their shareholders could be negatively impacted as a result.

ENERGY COMPANIES RISK. Certain Funds invest significantly in energy companies. The success of energy companies may be cyclical and highly dependent on energy prices. The market value of securities issued by energy companies may decline for many reasons, including, among other things, changes in the levels and volatility of global energy prices, energy supply and demand, capital expenditures on exploration and production of energy sources, exchange rates, interest rates, economic conditions, tax treatment, energy conservation efforts, increased competition and technological advances. Energy companies may be subject to substantial government regulation and contractual fixed pricing, which may increase the cost of doing business and limit the earnings of these companies. A significant portion of the revenues of these companies may depend on a relatively small number of customers, including governmental entities and utilities. As a result, governmental budget constraints may have a material adverse effect on the stock prices of energy companies. Energy companies may also operate in, or engage in transactions involving, countries with less developed regulatory regimes or a history of expropriation, nationalization or other adverse policies. Energy companies also face a significant risk of liability from accidents resulting in injury or loss of life or property, pollution or other environmental problems, equipment malfunctions or mishandling of materials and a risk of loss from terrorism, political strife or natural disasters. Energy companies can be significantly affected by the supply of, and demand for, specific products (e.g., oil and natural gas) and services, exploration and production spending, government subsidization, world events and general economic conditions. Energy companies may have relatively high levels of debt and may be more likely than other companies to restructure their businesses if there are downturns in energy markets or in the global economy.

EQUITY SECURITIES RISK. The value of a Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors' perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting the issuers occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market. Additionally, holders of an issuer's common stock may be subject to greater risks than holders of its preferred stock and debt securities because common stockholders' claims are subordinated to those of holders of preferred stocks and debt securities upon the bankruptcy of an issuer.

FINANCIAL COMPANIES RISK. Certain Funds invest significantly in financial companies. Financial companies are subject to extensive governmental regulation and intervention, which may adversely affect the scope of their activities, the prices they can charge, the amount and types of capital they must maintain and, potentially, their size. Governmental regulation may change frequently and may have significant adverse consequences for financial companies, including effects not intended by such regulation. The impact of more stringent capital requirements, or recent or future regulation in various countries, on any individual financial company or on financial companies as a whole cannot be predicted. Certain risks may impact the value of investments in financial companies more severely than those of investments in other issuers, including the risks associated with companies that operate with substantial financial leverage. Financial companies may also be adversely affected by volatility in interest rates, loan losses and other customer defaults, decreases in the availability of money or asset valuations, credit rating downgrades and adverse conditions in other related markets. Insurance companies in particular may be subject to severe price competition and/or rate regulation, which may have an adverse impact on their profitability. Financial companies are also a target for cyber attacks and may experience technology malfunctions and disruptions as a result.

GROWTH STOCKS INVESTMENT RISK. Certain Funds utilize a growth style of investing. Growth stocks generally are priced higher than non-growth stocks in relation to an issuer’s earnings and other measures because investors believe they have greater growth potential. However, there is no guarantee that such an issuer will realize that growth potential. In addition, the market values of growth stocks may be more volatile than other types of investments, and therefore more susceptible to rapid price swings, especially during periods of economic uncertainty or in response to adverse news about the condition of

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the issuer, such as earnings disappointments. The returns on growth stocks may or may not move in tandem with the returns on other styles of investing or the overall stock market. Growth stocks may fall out of favor and trail the returns of funds employing other styles of investing. Growth stocks may also be more adversely affected in a down market, as growth stocks typically have little or no dividend income to absorb the effect of adverse market conditions.

HEALTH CARE COMPANIES RISK. Certain Funds invest significantly in health care companies. Health care companies, such as companies providing medical and health care goods and services, companies engaged in manufacturing medical equipment, supplies and pharmaceuticals, as well as operating healthcare facilities and the provision of managed healthcare, may be affected by government regulations and government health care programs, increases or decreases in the cost of medical products and services and product liability claims, among other factors. Many health care companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Research and development costs of bringing new drugs to market are substantial, and there is no guarantee that a proposed product will ever come to market. Health care companies are also subject to competitive forces that may result in price discounting, may be thinly capitalized and susceptible to product obsolescence.

INDEX CONCENTRATION RISK. A Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that a Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if a Fund were more broadly diversified. A significant exposure makes a Fund more susceptible to any single occurrence and may subject a Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by a Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, a Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.

INDEX OR MODEL CONSTITUENT RISK. Each Fund may be a constituent of one or more indices or ETF models. As a result, a Fund may be included in one or more index-tracking ETFs or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving a Fund’s shares, the size of the Fund and the market volatility of the Fund’s shares. Inclusion in an index could increase demand for a Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, a Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity. To the extent buying or selling activity increases, a Fund can be exposed to increased brokerage costs and adverse tax consequences and the market price of the Fund can be negatively affected.

INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile an Index accurately, or that an Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. An Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in an Index, and do not guarantee that an Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage each Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate an Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by a Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of an Index or other modification of Index constituents or weightings. When a Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by a Fund and its shareholders. Unscheduled rebalances also expose a Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile an Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where an Index is less commonly used as a benchmark by funds or advisors. For example, during a period where an Index contains incorrect constituents, a Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact a Fund and its shareholders. An Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in an Index, including information that may be based on assumptions and estimates. Neither a Fund nor the Advisor can offer assurances that an Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security from the Index or undertake other measures which could cause an Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents

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that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of an Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to an Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.

INDUSTRIALS COMPANIES RISK. Certain Funds invest significantly in industrials companies. The value of securities issued by industrials companies may be adversely affected by supply and demand related to their specific products or services and industrials sector products in general. The products of manufacturing companies may face obsolescence due to rapid technological developments and frequent new product introduction. World events and changes in government regulations, import controls, economic conditions and exchange rates may adversely affect the performance of companies in the industrials sector. Industrials companies may be adversely affected by liability for environmental damage and product liability claims. Industrials companies may also be adversely affected by changes or trends in commodity prices, which may be influenced by unpredictable factors. Industrials companies, particularly aerospace and defense companies, may also be adversely affected by government spending policies because companies in this sector tend to rely to a significant extent on government demand for their products and services.

INFORMATION TECHNOLOGY COMPANIES RISK. Certain Funds invest significantly in information technology companies. Information technology companies produce and provide hardware, software and information technology systems and services. Information technology companies are generally subject to the following risks: rapidly changing technologies and existing product obsolescence; short product life cycles; fierce competition; aggressive pricing and reduced profit margins; the loss of patent, copyright and trademark protections; cyclical market patterns; evolving industry standards; and frequent new product introductions and new market entrants. Information technology companies may be smaller and less experienced companies, with limited product lines, markets or financial resources and fewer experienced management or marketing personnel. Information technology company stocks, particularly those involved with the internet, have experienced extreme price and volume fluctuations that are often unrelated to their operating performance. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also face competition for services of qualified personnel and heavily rely on patents and intellectual property rights and the ability to enforce such rights to maintain a competitive advantage.

LARGE CAPITALIZATION COMPANIES RISK. Certain Funds invest in the securities of large capitalization companies. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.

MARKET CAPITALIZATION DEVIATION RISK. Certain Funds seek to hold securities with a market capitalization that falls within a specific range. However, because of possible corporate action or market movement, there can be no assurance that the securities held by a Fund will stay within the Fund’s intended market capitalization range. As a result, a Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.

MARKET MAKER RISK. The Funds face numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of a Fund’s portfolio securities and the Fund’s market price. A Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between a Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.

MARKET RISK. Market risk is the risk that a particular investment, or shares of a Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of a Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on a Fund and its investments. Any of such circumstances could have

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a materially negative impact on the value of a Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, a Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on a Fund’s shares may widen and the returns on investment may fluctuate.

MATERIALS COMPANIES RISK. Certain Funds invest significantly in materials and processing companies. Materials and processing companies are involved in the extraction or processing of raw materials such as metals, ore and forestry products. Changes in world events, political and economic conditions, energy conservation, environmental policies, commodity price volatility, changes in currency exchange rates, imposition of import controls, increased competition, depletion of resources, technical progress and labor relations, among other factors, may adversely affect materials and processing companies. These companies are also at risk of liability for environmental damage and product liability claims. Production of materials may exceed demand as a result of market imbalances or economic downturns, leading to poor investment returns.

MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.

NON-CORRELATION RISK. A Fund’s return may not match the return of its Index for a number of reasons. A Fund incurs operating expenses not applicable to its Index and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, a Fund’s portfolio holdings may not exactly replicate the securities included in its Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, a Fund’s portfolio may deviate from the composition of its Index. Accordingly, a Fund's return may underperform the return of its Index.

OPERATIONAL RISK. Each Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of a Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. Each Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect each Fund's ability to meet its investment objective. Although the Funds and the Funds’ investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.

PASSIVE INVESTMENT RISK. The Funds are not actively managed. Each Fund invests in securities included in or representative of its Index regardless of investment merit. The Funds generally will not attempt to take defensive positions in declining markets. In the event that an Index is no longer calculated, the corresponding Index license is terminated or the identity or character of an Index is materially changed, the applicable Fund will seek to engage a replacement index.

PORTFOLIO TURNOVER RISK. Certain Funds have an investment strategy that may frequently involve buying and selling portfolio securities. High portfolio turnover may result in a Fund paying higher levels of transaction costs, including brokerage commissions, dealer mark-ups and other costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause a Fund’s performance to be less than expected.

PREMIUM/DISCOUNT RISK. The market price of a Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. First Trust cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of a Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), First Trust believes that large discounts or premiums to the net asset value of shares should not be sustained absent disruptions to the creation and redemption mechanism, extreme market volatility or potential lack of authorized participants. During stressed market conditions, the market for a Fund’s shares may become less liquid in response to deteriorating liquidity in the market for a Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of a Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.

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SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.

TRADING ISSUES RISK. Trading in Fund shares on an Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on an Exchange is subject to trading halts caused by extraordinary market volatility pursuant to an Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of an Exchange necessary to maintain the listing of a Fund will continue to be met or will remain unchanged. A Fund may have difficulty maintaining its listing on an Exchange in the event a Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.

UTILITY COMPANIES RISK. Certain Funds invest significantly in utility companies. Utility companies include companies producing or providing gas, electricity or water. The risks inherent in the utilities sector include a variety of factors that may adversely affect the business or operations of utility companies, including: high interest costs associated with capital construction and improvement programs; difficulty in raising adequate capital on reasonable terms in periods of high inflation and unsettled capital markets; governmental regulation of rates that the issuer can charge to customers; costs associated with compliance with, and adjusting to changes to, environmental and other regulations; effects of economic slowdowns and surplus capacity; increased competition from other providers of utilities services; costs associated with the reduced availability of certain types of fuel, occasionally reduced availability and high costs of natural gas for resale, and the effects of energy conservation policies. Some utility companies also face risks associated with the effects of a national energy policy and lengthy delays, and greatly increased costs and other problems, associated with the design, construction, licensing, regulation and operation of nuclear facilities for electric generation, including, among other considerations: the problems associated with the use of radioactive materials and the disposal of radioactive wastes; technological innovations that may render existing plants, equipment or products obsolete; difficulty in obtaining regulatory approval of new technologies; lack of compatibility of telecommunications equipment; potential impacts of terrorist activities on the utilities industry and its customers; and the impact of natural or man-made disasters. Utility companies may also be subject to regulation by various governmental authorities and may be affected by the imposition of special tariffs and changes in tax laws, regulatory policies and accounting standards. Deregulation is subjecting utility companies to greater competition and may adversely affect profitability. As deregulation allows utilities to diversify outside of their original geographic regions and their traditional lines of business, utility companies may engage in riskier ventures. There is no assurance that regulatory authorities will, in the future, grant rate increases, or that such increases will be adequate to permit the payment of dividends on stocks issued by a utility company.

VALUE STOCKS INVESTMENT RISK. Certain Funds utilize a value style of investing. A value style of investing focuses on undervalued companies with characteristics for improved valuations. Value stocks are subject to the risk that valuations never improve or that the returns on value stocks are less than returns on other styles of investing or the overall stock market. As a result, the value of a Fund’s investments will vary and at times may be lower or higher than that of other types of investments. Historically, value investments have performed best during periods of economic recovery. Therefore, the value investing style may over time go in and out of favor and may trail the returns of other styles of investing. Value stocks also may decline in price, even though in theory they are already underpriced.

Non-Principal Risks

BDC RISK. BDCs may carry risks similar to those of a private equity or venture capital fund. BDCs are not redeemable at the option of the shareholder and they may trade in the market at a discount to their net asset value. The BDCs held by a Fund may employ the use of leverage their portfolios through borrowings or the issuance of preferred stock. While leverage often serves to increase the yield of a BDC, this leverage also subjects a BDC to increased risks, including the likelihood of increased volatility and the possibility that a BDC’s common share income will fall if the dividend rate of the preferred shares or the interest rate on any borrowings rises.

BORROWING AND LEVERAGE RISK. If a Fund borrows money, it must pay interest and other fees, which may reduce the Fund’s returns. Any such borrowings are intended to be temporary. However, under certain market conditions, including periods of decreased liquidity, such borrowings might be outstanding for longer periods of time. As prescribed by the 1940 Act, a Fund will be required to maintain specified asset coverage of at least 300% with respect to any bank borrowing immediately following such borrowing and at all times thereafter. A Fund may be required to dispose of assets on unfavorable terms if market fluctuations or other factors reduce the Fund’s asset coverage to less than the prescribed amount.

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CASH TRANSACTIONS RISK. The Funds may, under certain circumstances, effect a portion of their creations and redemptions for cash rather than in-kind. As a result, an investment in such a Fund may be less tax-efficient than an investment in an ETF that effects its creations and redemptions only in-kind. ETFs are able to make in-kind redemptions and avoid being taxed on gains on the distributed portfolio securities at the fund level. A Fund that effects redemptions for cash may be required to sell portfolio securities in order to obtain the cash needed to distribute redemption proceeds. Any recognized gain on these sales by a Fund will generally cause the Fund to recognize a gain it might not otherwise have recognized, or to recognize such gain sooner than would otherwise be required if it were to distribute portfolio securities only in-kind. The Funds intend to distribute these gains to shareholders to avoid being taxed on this gain at the fund level and otherwise comply with the special tax rules that apply to it. This strategy may cause shareholders to be subject to tax on gains they would not otherwise be subject to, or at an earlier date than if they had made an investment in a different ETF. Moreover, cash transactions may have to be carried out over several days if the securities market is relatively illiquid and may involve considerable brokerage fees and taxes. These brokerage fees and taxes, which will be higher than if a Fund sold and redeemed its shares in-kind, will be passed on to those purchasing and redeeming Creation Units in the form of creation and redemption transaction fees. In addition, these factors may result in wider spreads between the bid and the offered prices of a Fund’s shares than for ETFs that distribute portfolio securities in-kind.

DEPOSITARY RECEIPTS RISK. Certain Funds invest in depositary receipts. Depositary receipts are securities issued by a bank or trust company reflecting ownership of underlying securities issued by a foreign company. An investment in depositary receipts involves further risks due to certain unique features. Any distributions paid to the holders of depositary receipts are usually subject to a fee charged by the depositary. Holders of depositary receipts may have limited voting rights pursuant to a deposit agreement between the underlying issuer and the depositary. In certain cases, the depositary will vote the shares deposited with it as directed by the underlying issuer’s board of directors. Furthermore, investment restrictions in certain countries may adversely impact the value of depositary receipts because such restrictions may limit the ability to convert shares into depositary receipts and vice versa. Such restrictions may cause shares of the underlying issuer to trade at a discount or premium to the market price of the depositary receipt. Moreover, if depositary receipts are converted into shares, the laws in certain countries may limit the ability of a non-resident to trade the shares and to reconvert the shares to depositary receipts. Depositary receipts may be “sponsored” or “unsponsored.” Sponsored depositary receipts are established jointly by a depositary and the underlying issuer, whereas unsponsored depositary receipts may be established by a depositary without participation by the underlying issuer. Holders of unsponsored depositary receipts generally bear all the costs associated with establishing the unsponsored depositary receipts. In addition, the issuers of the securities underlying unsponsored depositary receipts are not obligated to disclose material information in the U.S. and, therefore, there may be less information available regarding such issuers and there may not be a correlation between such information and the market value of the depositary receipts.

FAILURE TO QUALIFY AS A REGULATED INVESTMENT COMPANY RISK. If, in any year, a Fund fails to qualify as a regulated investment company under the applicable tax laws, that Fund would be taxed as an ordinary corporation. In such circumstances, the Fund's taxable income would be subject to tax at the Fund level and to a further tax at the shareholder level when such income is distributed and a Fund could be required to recognize unrealized gains, pay substantial taxes and interest and make substantial distributions before requalifying as a regulated investment company that is accorded special tax treatment. This would cause investors to incur higher tax liabilities than they otherwise would have incurred and would have a negative impact on Fund returns. If the Fund fails to qualify as a regulated investment company, distributions to the Fund's shareholders generally would be eligible (i) for treatment as qualified dividend income in the case of individual shareholders and (ii) for the dividends received deduction in the case of corporate shareholders. See "Federal Tax Matters."

INTELLECTUAL PROPERTY RISK. Each Fund relies on a license and related sublicense that permits a Fund to use its Index and associated trade names, trademarks and service marks (the “Intellectual Property”) in connection with the Fund’s name and investment strategies. Such license and related sublicense may be terminated by the Index Provider, and, as a result, a Fund may lose its ability to use the Intellectual Property. There is also no guarantee that the Index Provider has all rights to license the Intellectual Property for use by a Fund. Accordingly, in the event the license is terminated or the Index Provider does not have rights to license the Intellectual Property, it may have a significant effect on the operation of a Fund.

ISSUER SPECIFIC CHANGES RISK. The value of an individual security or particular type of security can be more volatile than the market as a whole and can perform differently from the value of the market as a whole.

LEGISLATION/LITIGATION RISK. From time to time, various legislative initiatives are proposed that may have a negative impact on certain securities in which the Funds invest. In addition, litigation regarding any of the securities owned by a Fund may negatively impact the value of the Fund’s shares. Such legislation or litigation may cause a Fund to lose value or may result in higher portfolio turnover if the Advisor determines to sell such a holding.

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MONEY MARKET/SHORT-TERM SECURITIES RISK. To the extent that a Fund invests in money market or short-term securities, the Fund may be subject to certain risks associated with such investments. An investment in a money market fund or short-term securities is not a bank deposit and is not insured or guaranteed by any bank, the Federal Deposit Insurance Corporation or any other government agency. It is possible for a Fund to lose money by investing in money market funds. A money market fund may not achieve its investment objective. Changes in government regulations may affect the value of an investment in a money market fund.

REAL ESTATE COMPANIES RISK. Certain Funds invest significantly in real estate companies. Real estate companies include REITs and other companies involved in the operation and development of commercial, residential and industrial real estate. An investment in a real estate company may be subject to risks similar to those associated with direct ownership of real estate, including the possibility of declines in the value of real estate, losses from casualty or condemnation, and changes in local and general economic conditions, supply and demand, interest rates, environmental liability, zoning laws, regulatory limitations on rents, property taxes, and operating expenses. Some real property companies have limited diversification because they invest in a limited number of properties, a narrow geographic area, or a single type of property. The performance of real estate companies has historically been cyclical and particularly sensitive to the overall economy and market changes, including declines in the value of real estate or, conversely, saturation of the real estate market, economic downturns and defaults by borrowers or tenants during such periods, increases in competition, possible lack of mortgage funds or other limits to accessing the credit or capital markets, and changes in interest rates.

REIT RISK. Certain Funds invest in REITs. REITs typically own and operate income-producing real estate, such as residential or commercial buildings, or real-estate related assets, including mortgages. As a result, investments in REITs are subject to the risks associated with investing in real estate, which may include, but are not limited to: fluctuations in the value of underlying properties; defaults by borrowers or tenants; market saturation; changes in general and local operating expenses; and other economic, political or regulatory occurrences affecting companies in the real estate sector. Additionally, investing in REITs involves certain other risks related to their structure and focus, which include, but are not limited to, dependency upon management skills, limited diversification, the risks of locating and managing financing for projects, heavy cash flow dependency, possible default by borrowers, the costs and potential losses of self-liquidation of one or more holdings, the risk of a possible lack of mortgage funds and associated interest rate risks, overbuilding, property vacancies, increases in property taxes and operating expenses, changes in zoning laws, losses due to environmental damages, changes in neighborhood values and appeal to purchasers, the possibility of failing to maintain exemptions from registration under the 1940 Act, failure to satisfy the requirements of the Internal Revenue Code of 1986 for maintaining REIT status and, in many cases, relatively small market capitalization, which may result in less market liquidity and greater price volatility for a REIT’s shares. REITs are also subject to the risk that the real estate market may experience an economic downturn generally, which may have a material effect on the real estate in which the REITs invest and their underlying portfolio securities.

REPURCHASE AGREEMENT RISK. Certain Funds may enter into repurchase agreements. A repurchase agreement is an agreement to purchase a security from a party at one price and a simultaneous agreement to sell it back to the original party at an agreed-upon price, typically representing the purchase price plus interest. Repurchase agreements may be viewed as loans made by a Fund which are collateralized by the securities subject to repurchase. A Fund's investment return on such transactions will depend on the counterparty's willingness and ability to perform its obligations under a repurchase agreement. If a Fund's counterparty should default on its obligations and a Fund is delayed or prevented from recovering the collateral, or if the value of the collateral is insufficient, a Fund may have to borrow cash, subject to certain legal limits, or realize a loss.

RESTRICTED SECURITIES RISK. Certain Funds invest in restricted securities. Restricted securities are securities that cannot be offered for public resale unless registered under the applicable securities laws or that have a contractual restriction that prohibits or limits their resale. Restricted securities include private placement securities that have not been registered under the applicable securities laws, such as Rule 144A securities, and securities of U.S. and non-U.S. issuers that are issued pursuant to Regulation S. Private placements are generally subject to strict restrictions on resale. Restricted securities may be illiquid as they generally are not listed on an exchange and may have no active trading market. A Fund may be unable to sell a restricted security on short notice or may be able to sell them only at a price below current value. It may be more difficult to determine a market value for a restricted security. Also, a Fund may get limited information about the issuer of a restricted security, so it may be less able to predict a loss. In addition, if Fund management receives material non-public information about the issuer, a Fund may as a result be unable to sell the securities. Certain restricted securities may involve a high degree of business and financial risk and may result in substantial losses.

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Fund Organization

Each Fund is a series of the Trust, an investment company registered under the 1940 Act. Each Fund is treated as a separate fund with its own investment objective and policies. The Trust is organized as a Massachusetts business trust. The Board is responsible for the overall management and direction of the Trust. The Board elects the Trust’s officers and approves all significant agreements, including those with the Advisor, distributor, custodian and fund administrative and accounting agent.

Management of the Funds

First Trust Advisors L.P., 120 East Liberty Drive, Wheaton, Illinois 60187, is the investment advisor to the Funds. In this capacity, First Trust is responsible for the selection and ongoing monitoring of the securities in each Fund’s portfolio and certain other services necessary for the management of the portfolios.

First Trust is a limited partnership with one limited partner, Grace Partners of DuPage L.P., and one general partner, The Charger Corporation. Grace Partners of DuPage L.P. is a limited partnership with one general partner, The Charger Corporation, and a number of limited partners. The Charger Corporation is an Illinois corporation controlled by James A. Bowen, the Chief Executive Officer of First Trust. First Trust discharges its responsibilities subject to the policies of the Funds.

First Trust serves as advisor or sub-advisor for 12 mutual fund portfolios, 10 exchange-traded funds consisting of 281 series and 6 closed-end funds. It is also the portfolio supervisor of certain unit investment trusts sponsored by First Trust Portfolios L.P. (“FTP”), an affiliate of First Trust, 120 East Liberty Drive, Wheaton, Illinois 60187. FTP specializes in the underwriting, trading and distribution of unit investment trusts and other securities. FTP is the principal underwriter of the shares of the Funds.

There is no one individual primarily responsible for portfolio management decisions for the Funds. Investments are made under the direction of the Investment Committee. The Investment Committee consists of Daniel J. Lindquist, David G. McGarel, Jon C. Erickson, Roger F. Testin, Stan Ueland, Chris A. Peterson and Erik Russo.

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Mr. Lindquist is Chairman of the Investment Committee and presides over Investment Committee meetings. Mr. Lindquist is responsible for overseeing the implementation of each Fund’s investment strategy. Mr. Lindquist was a Senior Vice President of First Trust and FTP from September 2005 to July 2012 and is now a Managing Director of First Trust and FTP. Mr. Lindquist is a recipient of the Chartered Financial Analyst designation.

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Mr. McGarel is the Chief Investment Officer, Chief Operating Officer and a Managing Director of First Trust and FTP. As First Trust’s Chief Investment Officer, Mr. McGarel consults with the other members of the Investment Committee on market conditions and First Trust’s general investment philosophy. Mr. McGarel was a Senior Vice President of First Trust and FTP from January 2004 to July 2012. Mr. McGarel is a recipient of the Chartered Financial Analyst designation.

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Mr. Erickson joined First Trust in 1994 and is a Senior Vice President of First Trust and FTP. As the head of First Trust’s Equity Research Group, Mr. Erickson is responsible for determining the securities to be purchased and sold by funds that do not utilize quantitative investment strategies. Mr. Erickson is a recipient of the Chartered Financial Analyst designation.

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Mr. Testin is a Senior Vice President of First Trust and FTP. Mr. Testin is the head of First Trust’s Portfolio Management Group. Mr. Testin has been a Senior Vice President of First Trust and FTP since November 2003. Mr. Testin is a recipient of the Chartered Financial Analyst designation.

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Mr. Ueland joined First Trust as a Vice President in August 2005 and has been a Senior Vice President of First Trust and FTP since September 2012. At First Trust, he plays an important role in executing the investment strategies of each portfolio of exchange-traded funds advised by First Trust.

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Mr. Peterson is a Senior Vice President and head of First Trust’s strategy research group. He joined First Trust in January of 2000. Mr. Peterson is responsible for developing and implementing quantitative equity investment strategies. Mr. Peterson received his B.S. in Finance from Bradley University in 1997 and his M.B.A. from the University of Chicago Booth School of Business in 2005. He has over 26 years of financial services industry experience and is a recipient of the Chartered Financial Analyst designation.

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Mr. Russo is a Vice President of First Trust. He is responsible for implementing the investment strategies of each portfolio of exchange-traded funds advised by First Trust in his role as a Portfolio Manager. Mr. Russo joined First Trust in January of 2010.

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For additional information concerning First Trust, including a description of the services provided to the Funds, see the Funds' SAI. Additional information about the compensation of Investment Committee members, other accounts managed by members of the Investment Committee and ownership by members of the Investment Committee of shares of the Funds is provided in the SAI.

Management Fee

Pursuant to an investment management agreement (the "Unitary Fee Investment Management Agreement") between First Trust and the Trust, on behalf of First Trust Mid Cap Growth AlphaDEX® Fund, First Trust Mid Cap Value AlphaDEX® Fund, First Trust Small Cap Growth AlphaDEX® Fund and First Trust Small Cap Value AlphaDEX® Fund (each a “Unitary Fee Fund”), First Trust manages each Unitary Fee Fund's assets. First Trust is paid an annual unitary management fee equal to 0.70% of each Unitary Fee Fund’s average daily net assets and is responsible for each Unitary Fee Fund’s expenses, including the cost of transfer agency, custody, fund administration, legal, audit, license and other services, and excluding fee payments under the Unitary Fee Investment Management Agreement, distribution and service fees, if any, brokerage expense, acquired fund fees and expenses, if any, taxes, interest, and other extraordinary expenses.

Pursuant to a separate investment management agreement (the "Expense Cap Investment Management Agreement") between First Trust and the Trust, on behalf of First Trust Consumer Discretionary AlphaDEX® Fund, First Trust Consumer Staples AlphaDEX® Fund, First Trust Energy AlphaDEX® Fund, First Trust Financials AlphaDEX® Fund, First Trust Health Care AlphaDEX® Fund, First Trust Industrials/Producer Durables AlphaDEX® Fund, First Trust Materials AlphaDEX® Fund, First Trust Technology AlphaDEX® Fund, First Trust Utilities AlphaDEX® Fund, First Trust Large Cap Core AlphaDEX® Fund, First Trust Large Cap Growth AlphaDEX® Fund, First Trust Large Cap Value AlphaDEX® Fund, First Trust Mid Cap Core AlphaDEX® Fund, First Trust Multi Cap Growth AlphaDEX® Fund, First Trust Multi Cap Value AlphaDEX® Fund and First Trust Small Cap Core AlphaDEX® Fund (each an “Expense Cap Fund”), First Trust manages each Expense Cap Fund's assets. First Trust is paid an annual management fee equal to 0.50% of each Expense Cap Fund’s average daily net assets. Additionally, First Trust and the Trust, on behalf of the Expense Cap Funds, have entered into an Expense Reimbursement and Fee Waiver Agreement (the “Agreement”) pursuant to which First Trust has agreed to waive fees and/or reimburse fund expenses to the extent that an Expense Cap Fund’s operating expenses (excluding interest expense, brokerage commissions and other trading expenses, acquired fund fees and expenses if any, taxes and extraordinary expenses) do not exceed 0.70% of average daily net assets (the “Expense Cap”) at least through November 30, 2025 (the “Expense Cap Termination Date”). Each Expense Cap Fund is responsible for all of its expenses, including management fees, costs of transfer agency, custody, fund administration, legal, audit and other services, interest, taxes, brokerage commissions and other expenses related to the execution of portfolio transactions, paying for its sublicensing fees related to the Expense Cap Fund’s Index, any distribution fees or expenses, and extraordinary expenses. First Trust has agreed to waive fees and/or pay Expense Cap Fund expenses to the extent necessary to prevent the annual operating expenses of each such Expense Cap Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) from exceeding the Expense Cap until the Expense Cap Termination Date.

The table below sets forth the annual management fee that First Trust may receive from each Fund. The table also sets forth the amounts paid by the Funds to First Trust for the fiscal year ended July 31, 2024 (net of fee waivers and/or expense reimbursements, as applicable) as a percentage of a Fund's average daily net assets. 

Fund	Annual Management Fee (% of average daily net assets)	Annual Expense Cap (% of average daily net assets)	Expense Cap Termination Date	Management Fee Paid for the Year Ended July 31, 2024 (% of average daily net assets)
First Trust Consumer Discretionary AlphaDEX® Fund (FXD)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Consumer Staples AlphaDEX® Fund (FXG)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Energy AlphaDEX® Fund (FXN)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Financials AlphaDEX® Fund (FXO)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Health Care AlphaDEX® Fund (FXH)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Materials AlphaDEX® Fund (FXZ)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Technology AlphaDEX® Fund (FXL)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Utilities AlphaDEX® Fund (FXU)	0.50%	0.70%	November 30, 2025	0.50%

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Fund	Annual Management Fee (% of average daily net assets)	Annual Expense Cap (% of average daily net assets)	Expense Cap Termination Date	Management Fee Paid for the Year Ended July 31, 2024 (% of average daily net assets)
First Trust Large Cap Core AlphaDEX® Fund (FEX)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Large Cap Growth AlphaDEX® Fund (FTC)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Large Cap Value AlphaDEX® Fund (FTA)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Mid Cap Core AlphaDEX® Fund (FNX)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Mid Cap Growth AlphaDEX® Fund (FNY)	0.70%	N/A	N/A	0.70%
First Trust Mid Cap Value AlphaDEX® Fund (FNK)	0.70%	N/A	N/A	0.70%
First Trust Multi Cap Growth AlphaDEX® Fund (FAD)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Multi Cap Value AlphaDEX® Fund (FAB)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Small Cap Core AlphaDEX® Fund (FYX)	0.50%	0.70%	November 30, 2025	0.50%
First Trust Small Cap Growth AlphaDEX® Fund (FYC)	0.70%	N/A	N/A	0.70%
First Trust Small Cap Value AlphaDEX® Fund (FYT)	0.70%	N/A	N/A	0.70%

As approved by the Trust’s Board of Trustees, the management fee paid to First Trust will be reduced at certain levels of Fund net assets (“breakpoints”). See the Fund's Statement of Additional Information for more information on the breakpoints.

A discussion regarding the Board’s approval of the continuation of the Investment Management Agreement is available in the Funds’ Form N-CSR for the fiscal year ended July 31, 2024.

How to Buy and Sell Shares

Most investors buy and sell shares of a Fund in secondary market transactions through brokers. Shares of each Fund are listed for trading on the secondary market on one or more national securities exchanges. Shares can be bought and sold throughout the trading day like other publicly traded shares. There is no minimum investment when buying shares on an Exchange. Although shares are generally purchased and sold in “round lots” of 100 shares, brokerage firms typically permit investors to purchase or sell shares in smaller “odd lots,” at no per-share price differential. When buying or selling shares through a broker, investors should expect to pay brokerage commissions, investors may receive less than the net asset value of the shares because shares are bought and sold at market prices rather than at net asset value, and investors may pay some or all of the bid-ask spread for each transaction (purchase or sale) of Fund shares. Share prices are reported in dollars and cents per share.

Under normal circumstances, a Fund will pay out redemption proceeds to a redeeming authorized participant within one day after the authorized participant’s redemption request is received, in accordance with the process set forth in a Fund’s SAI and in the agreement between the authorized participant and the Fund’s distributor. However, each Fund reserves the right, including under stressed market conditions, to take up to seven days after the receipt of a redemption request to pay an authorized participant, all as permitted by the 1940 Act. If a Fund has foreign investments in a country where a local market holiday, or series of consecutive holidays, or the extended delivery cycles for transferring foreign investments to redeeming authorized participants prevents the Fund from delivering such foreign investments to an authorized participant in response to a redemption request, a Fund may take up to 15 days after the receipt of the redemption request to deliver such investments to the authorized participant.

For purposes of the 1940 Act, each Fund is treated as a registered investment company and the acquisition of shares by other registered investment companies and companies relying on Sections 3(c)(1) or 3(c)(7) of the 1940 Act is subject to the restrictions of Section 12(d)(1) of the 1940 Act and the related rules and interpretations.

Book Entry

Shares are held in book-entry form, which means that no share certificates are issued. The Depository Trust Company (“DTC”) or its nominee is the record owner of all outstanding shares of a Fund and is recognized as the owner of all shares for all purposes.

Investors owning shares are beneficial owners as shown on the records of DTC or its participants. DTC serves as the securities depository for all shares. Participants in DTC include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner

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of shares, you are not entitled to receive physical delivery of share certificates or to have shares registered in your name, and you are not considered a registered owner of shares. Therefore, to exercise any right as an owner of shares, you must rely upon the procedures of DTC and its participants. These procedures are the same as those that apply to any other stocks that you hold in book-entry or “street name” form.

Share Trading Prices

The trading price of shares of a Fund on the secondary market is based on market price and may differ from such Fund’s daily net asset value and can be affected by market forces of supply and demand, economic conditions and other factors.

Frequent Purchases and Redemptions of the Funds' Shares

The Funds impose no restrictions on the frequency of purchases and redemptions (“market timing”). In determining not to approve a written, established policy, the Board evaluated the risks of market timing activities by the Funds' shareholders. The Board considered that the Funds' shares can only be purchased and redeemed directly from the Funds in Creation Units by broker-dealers and large institutional investors that have entered into participation agreements (i.e., authorized participants (“APs”)) and that the vast majority of trading in the Funds' shares occurs on the secondary market. Because the secondary market trades do not involve the Funds directly, it is unlikely those trades would cause many of the harmful effects of market timing, including dilution, disruption of portfolio management, increases in the Funds' trading costs and the realization of capital gains. With respect to trades directly with the Funds, to the extent effected in-kind (i.e., for securities), those trades do not cause any of the harmful effects that may result from frequent cash trades. To the extent that the Funds may effect the purchase or redemption of Creation Units in exchange wholly or partially for cash, the Board noted that such trades could result in dilution to a Fund and increased transaction costs, which could negatively impact the Funds' ability to achieve their investment objectives. However, the Board noted that direct trading by APs is critical to ensuring that the shares trade at or close to net asset value. In addition, the Funds impose fixed and variable transaction fees on purchases and redemptions of Creation Units to cover the custodial and other costs incurred by the Funds in effecting trades. Finally, the Advisor monitors purchase and redemption orders from APs for patterns of abusive trading and the Funds reserve the right to not accept orders from APs that the Advisor has determined may be disruptive to the management of the Funds.

Dividends, Distributions and Taxes

Dividends from net investment income from the Funds, if any, are declared and paid quarterly by each Fund. Each Fund distributes its net realized capital gains, if any, to shareholders at least annually.

Distributions in cash may be reinvested automatically in additional whole shares only if the broker through whom you purchased shares makes such option available. Such shares will generally be reinvested by the broker based upon the market price of those shares and investors may be subject to customary brokerage commissions charged by the broker.

Federal Tax Matters

This section summarizes some of the main U.S. federal income tax consequences of owning shares of the Funds. This section is current as of the date of this prospectus. Tax laws and interpretations change frequently, and these summaries do not describe all of the tax consequences to all taxpayers. For example, these summaries generally do not describe your situation if you are a corporation, a non-U.S. person, a broker-dealer, or other investor with special circumstances. In addition, this section does not describe your state, local or non-U.S. tax consequences.

This federal income tax summary is based in part on the advice of counsel to the Funds. The Internal Revenue Service ("IRS") could disagree with any conclusions set forth in this section. The following disclosure may not be sufficient for you to use for the purpose of avoiding penalties under federal tax law.

As with any investment, you should seek advice based on your individual circumstances from your own tax advisor.

Fund Status

Each Fund intends to continue to qualify as a “regulated investment company” (a “RIC”) under the federal tax laws. If a Fund qualifies as a RIC and distributes its income as required by the tax law, the Fund generally will not pay federal income taxes.

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Distributions

The Funds’ distributions are generally taxable. After the end of each year, you will receive a tax statement that separates the distributions of a Fund into two categories, ordinary income distributions and capital gain dividends. Ordinary income distributions are generally taxed at your ordinary tax rate; however, as further discussed below, certain ordinary income distributions received from a Fund may be taxed at the capital gain tax rates. Some portion of the ordinary income distributions that are attributable to dividends received by a Fund from shares in certain real estate investment trusts may be designated by the Fund as eligible for a deduction for qualified business income, provided certain holding period requirements are satisfied. Generally, you will treat all capital gain dividends as long-term capital gains regardless of how long you have owned your shares.

To determine your actual tax liability for your capital gain dividends, you must calculate your total net capital gain or loss for the tax year after considering all of your other taxable transactions, as described below. In addition, the Funds may make distributions that represent a return of capital for tax purposes and thus will generally not be taxable to you; however, such distributions may reduce your tax basis in your shares, which could result in you having to pay higher taxes in the future when shares are sold, even if you sell the shares at a loss from your original investment. A “return of capital” is a return, in whole or in part, of the funds that you previously invested in the Fund. A return of capital distribution should not be considered part of a Fund’s dividend yield or total return of an investment in Fund shares. The tax status of your distributions from a Fund is not affected by whether you reinvest your distributions in additional shares or receive them in cash. The tax laws may require you to treat distributions made to you in January as if you had received them on December 31 of the previous year.

Income from a Fund may also be subject to a 3.8% “Medicare tax.” This tax generally applies to your net investment income if your adjusted gross income exceeds certain threshold amounts, which are $250,000 in the case of married couples filing joint returns and $200,000 in the case of single individuals.

Dividends Received Deduction

A corporation that owns shares generally will not be entitled to the dividends received deduction with respect to many dividends received from a Fund because the dividends received deduction is generally not available for distributions from RICs. However, certain ordinary income dividends on shares that are attributable to qualifying dividends received by the Funds from certain corporations may be reported by the Funds as being eligible for the dividends received deduction.

Capital Gains and Losses and Certain Ordinary Income Dividends

If you are an individual, the maximum marginal stated federal tax rate for net capital gain is generally 20% (15% or 0% for taxpayers with taxable incomes below certain thresholds). Some capital gains, including some portion of your capital gain dividends may be taxed at a higher maximum stated federal tax rate. Capital gain received from assets held for more than one year that is considered “unrecaptured section 1250 gain” (which may be the case, for example, with some capital gains attributable to equity interests in real estate investment trusts that constitute interests in entities treated as real estate investment trusts for federal income tax purposes) is taxed at a maximum marginal stated federal tax rate of 25%. In the case of capital gain dividends, the determination of which portion of the capital gain dividend, if any, is subject to the 25% tax rate, will be made based on rules prescribed by the United States Treasury. Capital gains may also be subject to the Medicare tax described above.

Net capital gain equals net long-term capital gain minus net short-term capital loss for the taxable year. Capital gain or loss is long-term if the holding period for the asset is more than one year and is short-term if the holding period for the asset is one year or less. You must exclude the date you purchase your shares to determine your holding period. However, if you receive a capital gain dividend from a Fund and sell your share at a loss after holding it for six months or less, the loss will be recharacterized as long-term capital loss to the extent of the capital gain dividend received. The tax rates for capital gains realized from assets held for one year or less are generally the same as for ordinary income. The Internal Revenue Code of 1986, as amended, treats certain capital gains as ordinary income in special situations.

An election may be available to you to defer recognition of the gain attributable to a capital gain dividend if you make certain qualifying investments within a limited time. You should talk to your tax advisor about the availability of this deferral election and its requirements.

Ordinary income dividends received by an individual shareholder from a RIC such as each of the Funds are generally taxed at the same rates that apply to net capital gain (as discussed above), provided certain holding period requirements are satisfied and provided the dividends are attributable to qualifying dividends received by the Funds themselves. Distributions with respect to shares in real estate investment trusts and foreign corporations are qualifying dividends only in limited circumstances. Each

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Fund will provide notice to its shareholders of the amount of any distribution which may be taken into account as a dividend which is eligible for the capital gains tax rates.

Sale of Shares

If you sell or redeem your shares, you will generally recognize a taxable gain or loss. To determine the amount of this gain or loss, you must subtract your tax basis in your shares from the amount you receive in the transaction. Your tax basis in your shares is generally equal to the cost of your shares, generally including brokerage fees, if any. In some cases, however, you may have to adjust your tax basis after you purchase your shares. An election may be available to you to defer recognition of capital gain if you make certain qualifying investments within a limited time. You should talk to your tax advisor about the availability of this deferral election and its requirements.

Taxes on Purchase and Redemption of Creation Units

If you exchange securities for Creation Units, you will generally recognize a gain or a loss. The gain or loss will be equal to the difference between the market value of the Creation Units at the time and your aggregate basis in the securities surrendered and the cash component paid. If you exchange Creation Units for securities, you will generally recognize a gain or loss equal to the difference between your basis in the Creation Units and the aggregate market value of the securities received and the cash redemption amount. The IRS, however, may assert that a loss realized upon an exchange of securities for Creation Units or Creation Units for securities cannot be deducted currently under the rules governing “wash sales,” or on the basis that there has been no significant change in economic position.

Treatment of Fund Expenses

Expenses incurred and deducted by the Funds will generally not be treated as income taxable to you.

Non-U.S. Tax Credit

Because the Funds may invest in non-U.S. securities, the tax statement that you receive may include an item showing non-U.S. taxes a Fund paid to other countries. In this case, dividends taxed to you will include your share of the taxes such Fund paid to other countries. You may be able to deduct or receive a tax credit for your share of these taxes.

Non-U.S. Investors

If you are a non-U.S. investor (i.e., an investor other than a U.S. citizen or resident or a U.S. corporation, partnership, estate or trust), you should be aware that, generally, subject to applicable tax treaties, distributions from a Fund will be characterized as dividends for federal income tax purposes (other than dividends which a Fund properly reports as capital gain dividends) and will be subject to U.S. federal income taxes, including withholding taxes, subject to certain exceptions described below. However, distributions received by a non-U.S. investor from a Fund that are properly reported by a Fund as capital gain dividends may not be subject to U.S. federal income taxes, including withholding taxes, provided that a Fund makes certain elections and certain other conditions are met. Distributions from a Fund that are properly reported by the Fund as an interest-related dividend attributable to certain interest income received by the Fund or as a short-term capital gain dividend attributable to certain net short-term capital gain income received by the Fund may not be subject to U.S. federal income taxes, including withholding taxes when received by certain non-U.S. investors, provided that the Fund makes certain elections and certain other conditions are met. For tax years after December 31, 2022, amounts paid to or recognized by a non-U.S. affiliate that are excluded from tax under the portfolio interest, capital gain dividends, short-term capital gains or tax-exempt interest dividend exceptions or applicable treaties, may be taken into consideration in determining whether a corporation is an “applicable corporation” subject to a 15% minimum tax on adjusted financial statement income.

Distributions may be subject to a U.S. withholding tax of 30% in the case of distributions to (i) certain non-U.S. financial institutions that have not entered into an agreement with the U.S. Treasury to collect and disclose certain information and are not resident in a jurisdiction that has entered into such an agreement with the U.S. Treasury and (ii) certain other non-U.S. entities that do not provide certain certifications and information about the entity’s U.S. owners. This withholding tax is also currently scheduled to apply to the gross proceeds from the disposition of securities that produce U.S. source interest or dividends. However, proposed regulations may eliminate the requirement to withhold on payments of gross proceeds from dispositions.

Investments in Certain Non-U.S. Corporations

If a Fund holds an equity interest in any “passive foreign investment companies” (“PFICs”), which are generally certain non-U.S. corporations that receive at least 75% of their annual gross income from passive sources (such as interest, dividends, certain

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rents and royalties or capital gains) or that hold at least 50% of their assets in investments producing such passive income, a Fund could be subject to U.S. federal income tax and additional interest charges on gains and certain distributions with respect to those equity interests, even if all the income or gain is timely distributed to its shareholders. A Fund will not be able to pass through to its shareholders any credit or deduction for such taxes. A Fund may be able to make an election that could ameliorate these adverse tax consequences. In this case, a Fund would recognize as ordinary income any increase in the value of such PFIC shares, and as ordinary loss any decrease in such value to the extent it did not exceed prior increases included in income. Under this election, a Fund might be required to recognize in a year income in excess of its distributions from PFICs and its proceeds from dispositions of PFIC stock during that year, and such income would nevertheless be subject to the distribution requirement and would be taken into account for purposes of the 4% excise tax. Dividends paid by PFICs are not treated as qualified dividend income.

Distribution Plan

FTP serves as the distributor of Creation Units for the Funds on an agency basis. FTP does not maintain a secondary market in shares.

The Board has adopted a Distribution and Service Plan pursuant to Rule 12b-1 under the 1940 Act. In accordance with the Rule 12b-1 plan, the Funds are authorized to pay an amount up to 0.25% of their average daily net assets each year to reimburse FTP for amounts expended to finance activities primarily intended to result in the sale of Creation Units or the provision of investor services. FTP may also use this amount to compensate securities dealers or other persons that are APs for providing distribution assistance, including broker-dealer and shareholder support and educational and promotional services.

The Funds do not currently pay 12b-1 fees, and pursuant to a contractual arrangement, the Funds will not pay 12b-1 fees any time before November 30, 2025. However, in the event 12b-1 fees are charged in the future, because these fees are paid out of the Funds' assets, over time these fees will increase the cost of your investment and may cost you more than certain other types of sales charges.

Net Asset Value

Each Fund’s net asset value (“NAV”) is determined as of the close of regular trading (normally 4:00 p.m., Eastern Time) on each day the New York Stock Exchange (“NYSE”) is open for trading. If the NYSE closes early on a valuation day, a Fund’s NAV will be determined as of that time. Each Fund’s NAV is calculated by dividing the value of the net assets of the Fund (i.e., the value of its total assets less total liabilities) by the total number of outstanding shares of the Fund, generally rounded to the nearest cent.

Section 2(a)(41) of the 1940 Act provides that when a market quotation is readily available for a fund’s portfolio investment, it must be valued at the market value. Rule 2a-5 under the 1940 Act (“Rule 2a-5”) defines a readily available market quotation as “a quoted price (unadjusted) in active markets for identical investments that the fund can access at the measurement date, provided that a quotation will not be readily available if it is not reliable.” If a market quotation is not “readily available,” then the portfolio investment must be fair valued as determined in good faith by a fund’s board of trustees.

Rule 2a-5 permits a fund’s board of trustees to designate the fund’s investment adviser as its “valuation designee” to perform fair value determinations, subject to certain conditions. Accordingly, the Funds’ Board has designated First Trust as its valuation designee (the “Valuation Designee”) pursuant to Rule 2a-5 and has directed the Valuation Designee to perform the functions required in Rule 2a-5(a) subject to the requirements of Rule 2a-5(b) on behalf of all portfolio investments of the Funds, subject to the Board’s oversight. First Trust has established a pricing committee (the “Pricing Committee”) to assist in the administration of the duties of the Valuation Designee. The Valuation Designee has adopted valuation procedures for the First Trust Funds (the “Valuation Procedures”), a brief summary of which is set forth below.

The Pricing Committee has identified certain portfolio investments that are routinely categorized as having a readily available market quotation. The market value of an investment with a readily available market quotation is typically determined on the basis of official closing prices or last reported sale prices or equivalent price, although this can vary based on investment type and/or the availability of such prices.

The Pricing Committee has also identified certain portfolio investments that are routinely categorized as fair valued investments. In general, for such investments, the Funds’ accounting agent will obtain all pricing data for use in valuing such investments from a pricing service provider approved by the Pricing Committee (each, a “Pricing Service Provider”), subject to the oversight of the Pricing Committee. Pricing Service Providers typically value non-exchange-traded instruments utilizing a range of

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market-based inputs and assumptions. For example, when available, Pricing Service Providers may utilize inputs such as benchmark yields, reported trades, broker-dealer quotes, spreads, and transactions for comparable instruments. In pricing certain instruments, a Pricing Service Provider may consider information about an instrument’s issuer or market activity. Pricing Service Provider valuations of non-exchange-traded instruments generally represent the service’s good faith opinion as to what the holder of an instrument would receive in an orderly transaction for an institutional round lot position under current market conditions. Certain exchange-traded options, such as FLEX Options, are typically valued using a model-based price provided by a Pricing Service Provider.

Portfolio investments trading on foreign exchanges or over-the-counter markets that close prior to the close of the NYSE may be fair valued using a systematic fair valuation model provided by a Pricing Service Provider. If these foreign securities meet certain criteria in relation to the valuation model, their valuation is systematically adjusted to reflect the impact of movement in the U.S. market after the close of certain foreign markets.

If no price is available from a Pricing Service Provider or if the Pricing Committee has reason to question the accuracy or the reliability of a price supplied for a portfolio investment or the use of amortized cost, the Pricing Committee will determine the fair value of such portfolio investment in a manner that it believes most appropriately reflects the fair value of the portfolio investment on the valuation date (a “Special Fair Value Pricing Situation”). In a Special Fair Value Pricing Situation, the Pricing Committee will determine a fair value price subject to the process outlined in the Valuation Procedures and based on a consideration of all available information to the Pricing Committee at the time of the determination.

Additionally, for foreign securities, if an extraordinary market event occurs between the time the last “current” market quotation is available for a security in a Fund’s portfolio and the time the Fund’s NAV is determined that calls into doubt whether that earlier market quotation represents fair value at the time the Fund’s NAV is determined, the Pricing Committee will determine the fair valuation as set forth in the Valuation Procedures.

Fair value represents a good faith approximation of the value of a portfolio investment and is the amount a Fund might reasonably expect to receive from the current sale of that investment in an arm’s-length transaction. Valuing a Fund’s investments using fair value pricing will result in prices that may differ from current market valuations, if any, and that may not be the prices at which those investments could have been sold during the period in which the particular fair values were used. While the Valuation Procedures and Valuation Designee’s processes are intended to result in a Fund’s NAV calculation that fairly reflects the values as of the time of pricing, the fair value determined for a portfolio instrument may be materially different from the value that could be realized upon the sale of that instrument.

Foreign currencies are translated into U.S. dollars at the exchange rate of such currencies against the U.S. dollar as provided by a Pricing Service Provider. All assets denominated in foreign currencies will be converted into U.S. dollars at the exchange rates in effect at the time of valuation.

Fund Service Providers

The Bank of New York Mellon, 240 Greenwich Street, New York, New York 10286, acts as the administrator, custodian and fund accounting and transfer agent for the Funds. Chapman and Cutler LLP, 320 South Canal St., Chicago, Illinois 60606, serves as legal counsel to the Funds.

Index Providers

The Indices are compiled by the Index Providers. The Index Providers are not affiliated with the Funds, FTP or First Trust. Each Fund is entitled to use the applicable Index pursuant to a sublicensing arrangement by and among the Fund, Index Provider, First Trust and FTP, which in turn has a license agreement with the Index Provider. Each Index Provider, or its agent, also serves as the index calculation agent for each Index. The index calculation agent intends to calculate and disseminate the values of the Indices at least once every 15 seconds.

Disclaimers

First Trust does not guarantee the accuracy and/or the completeness of the Indices or any data included therein and First Trust shall have no liability for any errors, omissions or interruptions therein. First Trust makes no warranty, express or implied, as to results to be obtained by the Funds, owners of the shares of the Funds or any other person or entity from the use of the Indices or any data included therein. First Trust makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Indices or any data included therein. Without

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limiting any of the foregoing, in no event shall First Trust have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) arising out of matters relating to the use of the Indices, even if notified of the possibility of such damages.

“AlphaDEX®” is a registered trademark of FTP. The Trust, and First Trust on behalf of the Trust, has been granted the right by FTP to use the name “AlphaDEX®” for certain purposes.

AlphaDEX® Sector Funds

Source IDI Indices, LLC (“IDI”), is used with permission. “StrataQuant®” is a service/trade mark of IDI or its affiliates. Frank Russell Company is the source and owner of the trademarks, service marks and copyrights related to the Russell Indexes. Russell®, Russell 1000® and Russell 3000® are all registered trademarks of Frank Russell Company. Russell 1000® and Russell 3000® are being utilized in the Indices under license. These trademarks have been licensed, along with the StrataQuant® Consumer Discretionary Index, the StrataQuant® Consumer Staples Index, the StrataQuant® Energy Index, the StrataQuant® Financial Index, the StrataQuant® Health Care Index, the StrataQuant® Industrials Index, the StrataQuant® Materials Index, the StrataQuant® Technology Index and the StrataQuant® Utilities Index, (each an “Index,” collectively the “Indices”) for use by FTP in connection with the First Trust Consumer Discretionary AlphaDex® Fund (FXD), the First Trust Consumer Staples AlphaDEX® Fund (FXG), the First Trust Energy AlphaDEX® Fund (FXN), the First Trust Financials AlphaDEX® Fund (FXO), the First Trust Health Care AlphaDEX® Fund (FXH), the First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR), the First Trust Materials AlphaDEX® Fund (FXZ), First Trust Technology AlphaDEX® Fund (FXL), and the First Trust Utilities AlphaDEX® Fund (FXU) (each the “Product”). Neither FTP, First Trust Exchange-Traded AlphaDEX® Fund (the “Trust”) nor the Product, as applicable, is sponsored, endorsed, sold or promoted by IDI Indices, LLC, its affiliates or its Third Party Suppliers, including, without limitation, Frank Russell Company (“IDI and its Suppliers”). IDI and its Suppliers make no representations or warranties regarding the advisability of investing in securities generally, in the Product particularly, the Trust or the ability of the Index to track general stock market performance. IDI’s only relationship to FTP is the licensing of certain trademarks and trade names and the Index or components thereof. The Index is determined, composed and calculated by IDI without regard to the Licensee or the Product or its holders. IDI has no obligation to take the needs of the Licensee or the holders of the Product into consideration in determining, composing or calculating the Index. IDI is not responsible for and has not participated in the determination of the timing of, prices of, or quantities of the Product to be issued or in the determination or calculation of the equation by which the Product is to be priced, sold, purchased, or redeemed. Except for certain custom index calculation services, all information provided by IDI is general in nature and not tailored to the needs of Licensee or any other person, entity or group of persons. IDI has no obligation or liability in connection with the administration, marketing, or trading of the Product. IDI is not an investment advisor. Inclusion of a security within an index is not a recommendation by IDI to buy, sell, or hold such security, nor is it considered to be investment advice.

FTP has licensed to IDI, free of charge, the right to use certain intellectual property owned by FTP, including the AlphaDEX® trademark and the AlphaDEX® stock selection method, in connection with the creation of the StrataQuant® Series Indices. FTP has received a patent on the AlphaDEX® stock selection method from the United States Patent and Trademark Office. Notwithstanding such license, IDI is solely responsible for the creation, compilation and administration of the StrataQuant® Series Indices and has the exclusive right to determine the stocks included in the Indices and the Indices’ methodologies.

IDI AND ITS SUPPLIERS DISCLAIM ANY AND ALL WARRANTIES AND REPRESENTATIONS, EXPRESS AND/OR IMPLIED, INCLUDING ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE, INCLUDING THE INDICES, INDEX DATA AND ANY INFORMATION INCLUDED IN, RELATED TO, OR DERIVED THEREFROM (“INDEX DATA”). IDI AND ITS SUPPLIERS SHALL NOT BE SUBJECT TO ANY DAMAGES OR LIABILITY WITH RESPECT TO THE ADEQUACY, ACCURACY, TIMELINESS OR COMPLETENESS OF THE INDICES AND THE INDEX DATA, WHICH ARE PROVIDED ON AN “AS IS” BASIS AND YOUR USE IS AT YOUR OWN RISK.

AlphaDEX® Style Funds

FTP has licensed to Nasdaq, Inc., free of charge, the right to use certain intellectual property owned by FTP, including the AlphaDEX® trademark and the AlphaDEX® stock selection method, in connection with Nasdaq, Inc.’s creation of the Indices tracked by the AlphaDEX Style Funds (the "Nasdaq Indices"). Notwithstanding such license, Nasdaq, Inc. is solely responsible for the creation, compilation and administration of the Nasdaq Indices and has the exclusive right to determine the stocks included in the Nasdaq Indices and the Nasdaq Indices’ methodologies.

The AlphaDEX® Style Funds are not sponsored, endorsed, sold or promoted by Nasdaq, Inc. or its affiliates (Nasdaq, Inc., with its affiliates, are referred to as the “Corporations”). The Corporations have not passed on the legality or suitability of, or the accuracy or adequacy of descriptions and disclosures relating to, the AlphaDEX® Style Funds. The Corporations make no

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representation or warranty, express or implied to the owners of the AlphaDEX® Style Funds or any member of the public regarding the advisability of investing in securities generally or in the AlphaDEX® Style Funds particularly, or the ability of the Indices to track general market performance. The Corporations’ only relationship to First Trust (“Licensee”) is in the licensing of “Nasdaq” and the Nasdaq Indices’ registered trademarks, trade names and service marks of the Corporations and the use of the Nasdaq Indices which are determined, composed and calculated by the Corporations without regard to Licensee or the AlphaDEX® Style Funds. Nasdaq, Inc. has no obligation to take the needs of the Licensee or the owners of the AlphaDEX® Style Funds into consideration in determining, composing or calculating the Nasdaq Indices. The Corporations are not responsible for and have not participated in the determination of the timing of, prices at, or quantities of the AlphaDEX® Style Funds to be issued or in the determination or calculation of the equation by which an AlphaDEX® Style Fund is to be converted into cash. The Corporations have no liability in connection with the administration, marketing or trading of the AlphaDEX® Style Funds.

THE CORPORATIONS DO NOT GUARANTEE THE ACCURACY AND/OR UNINTERRUPTED CALCULATION OF THE NASDAQ INDICES OR ANY DATA INCLUDED THEREIN. THE CORPORATIONS MAKE NO WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY LICENSEE, OWNERS OF THE ALPHADEX® STYLE FUNDS, OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE NASDAQ INDICES OR ANY DATA INCLUDED THEREIN. THE CORPORATIONS MAKE NO EXPRESS OR IMPLIED WARRANTIES, AND EXPRESSLY DISCLAIM ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE WITH RESPECT TO THE NASDAQ INDICES OR ANY DATA INCLUDED THEREIN. WITHOUT LIMITING ANY OF THE FOREGOING, IN NO EVENT SHALL THE CORPORATIONS HAVE ANY LIABILITY FOR ANY LOST PROFITS OR SPECIAL, INCIDENTAL, PUNITIVE, INDIRECT, OR CONSEQUENTIAL DAMAGES, EVEN IF NOTIFIED OF THE POSSIBILITY OF SUCH DAMAGES.

Premium/Discount Information

Information showing the number of days the market price of each Fund's shares was greater (at a premium) and less (at a discount) than each Fund's net asset value for the most recently completed year, and the most recently completed calendar quarters since that year (or life of a Fund, if shorter), is available at http://www.ftportfolios.com/Retail/etf/home.aspx.

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Financial Highlights

The financial highlights table is intended to help you understand each Fund's financial performance for the periods shown. Certain information reflects financial results for a single share of the Funds. The total returns represent the rate that an investor would have earned (or lost) on an investment in a Fund (assuming reinvestment of all dividends and distributions). The information for the periods indicated has been derived from financial statements audited by Deloitte & Touche LLP, whose report, along with each Fund's financial statements, is included in the Funds' Form N-CSR dated July 31, 2024 and is incorporated by reference in each Fund's SAI, which is available upon request.

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Consumer Discretionary AlphaDEX® Fund (FXD) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$57.41	$49.57	$61.36	$39.70	$43.40
Income from investment operations:
Net investment income (loss)	0.41 (a)	0.35 (a)	0.52	0.20	0.36
Net realized and unrealized gain (loss)	3.29	7.95	(11.78 )	21.61	(3.61 )
Total from investment operations	3.70	8.30	(11.26 )	21.81	(3.25 )
Distributions paid to shareholders from:
Net investment income	(0.40 )	(0.46 )	(0.53 )	(0.15 )	(0.45 )
Net asset value, end of period	$60.71	$57.41	$49.57	$61.36	$39.70
Total Return (b)	6.47 %	16.93 %	(18.43 )%	54.99 %	(7.39 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,481,355	$1,504,179	$394,117	$1,948,136	$948,948
Ratio of total expenses to average net assets	0.61 %	0.61 %	0.61 %	0.61 %	0.63 %
Ratio of net investment income (loss) to average net assets	0.72 %	0.71 %	0.82 %	0.38 %	0.77 %
Portfolio turnover rate (c)	84 %	110 %	76 %	88 %	115 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

186

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Consumer Staples AlphaDEX® Fund (FXG) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$64.37	$63.79	$56.21	$48.76	$45.80
Income from investment operations:
Net investment income (loss)	0.92 (a)	1.20 (a)	0.81	0.79	0.84
Net realized and unrealized gain (loss)	2.05 (b)	0.56	7.55	7.40	2.98
Total from investment operations	2.97	1.76	8.36	8.19	3.82
Distributions paid to shareholders from:
Net investment income	(0.95 )	(1.18 )	(0.78 )	(0.74 )	(0.86 )
Net asset value, end of period	$66.39	$64.37	$63.79	$56.21	$48.76
Total Return (c)	4.69 %	2.87 %	14.95 %	16.88 %	8.46 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$414,948	$656,528	$650,653	$247,311	$258,429
Ratio of total expenses to average net assets	0.62 %	0.63 %	0.63 %	0.64 %	0.63 %
Ratio of net investment income (loss) to average net assets	1.46 %	1.92 %	1.41 %	1.43 %	1.72 %
Portfolio turnover rate (d)	67 %	63 %	88 %	94 %	113 %

(a)

Based on average shares outstanding.

(b)

The per share amount does not correlate with the aggregate realized and unrealized gain (loss) due to the timing of the Fund share sales and repurchases in relation to market value fluctuation of the underlying investments.

(c)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(d)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

187

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Energy AlphaDEX® Fund (FXN) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$17.25	$16.80	$10.33	$6.54	$10.88
Income from investment operations:
Net investment income (loss)	0.34 (a)	0.52 (a)	0.27	0.31	0.16
Net realized and unrealized gain (loss)	1.04	0.50 (b)	6.46	3.81	(4.31 )
Total from investment operations	1.38	1.02	6.73	4.12	(4.15 )
Distributions paid to shareholders from:
Net investment income	(0.34 )	(0.57 )	(0.26 )	(0.33 )	(0.19 )
Net asset value, end of period	$18.29	$17.25	$16.80	$10.33	$6.54
Total Return (c)	8.08 %	6.38 %	65.76 %	66.66 %	(38.32 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$548,790	$567,687	$1,665,291	$328,966	$615,795
Ratio of total expenses to average net assets	0.61 %	0.62 %	0.61 %	0.64 %	0.64 %
Ratio of net investment income (loss) to average net assets	1.93 %	3.01 %	2.34 %	1.70 %	2.39 %
Portfolio turnover rate (d)	60 %	58 %	79 %	71 %	165 %

(a)

Based on average shares outstanding.

(b)

The per share amount does not correlate with the aggregate realized and unrealized gain (loss) due to the timing of the Fund share sales and repurchases in relation to market value fluctuation of the underlying investments.

(c)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(d)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

188

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Financials AlphaDEX® Fund (FXO) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$41.49	$41.48	$43.40	$25.87	$32.35
Income from investment operations:
Net investment income (loss)	1.10 (a)	1.28 (a)	0.92	0.81	0.72
Net realized and unrealized gain (loss)	9.11	(0.05 )	(1.97 )	17.55	(6.37 )
Total from investment operations	10.21	1.23	(1.05 )	18.36	(5.65 )
Distributions paid to shareholders from:
Net investment income	(1.19 )	(1.22 )	(0.87 )	(0.83 )	(0.83 )
Net asset value, end of period	$50.51	$41.49	$41.48	$43.40	$25.87
Total Return (b)	25.17 %	3.24 %	(2.52 )%	71.99 %	(17.56 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$904,182	$894,024	$1,171,738	$1,312,886	$538,172
Ratio of total expenses to average net assets	0.61 %	0.62 %	0.62 %	0.61 %	0.62 %
Ratio of net investment income (loss) to average net assets	2.57 %	3.06 %	2.10 %	2.25 %	2.36 %
Portfolio turnover rate (c)	75 %	78 %	64 %	86 %	90 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

189

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Health Care AlphaDEX® Fund (FXH) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$106.42	$108.57	$122.03	$95.29	$77.62
Income from investment operations:
Net investment income (loss)	0.38 (a)	0.21 (a)	0.13	(0.15 )	0.01
Net realized and unrealized gain (loss)	2.74	(2.06 )	(13.59 )	26.89	17.66
Total from investment operations	3.12	(1.85 )	(13.46 )	26.74	17.67
Distributions paid to shareholders from:
Net investment income	(0.38 )	(0.30 )	—	—	—
Net asset value, end of period	$109.16	$106.42	$108.57	$122.03	$95.29
Total Return (b)	2.95 %	(1.69 )%	(11.03 )%	28.08 %	22.75 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,266,313	$1,521,820	$1,503,728	$1,604,748	$1,348,309
Ratio of total expenses to average net assets	0.60 %	0.62 %	0.61 %	0.61 %	0.61 %
Ratio of net investment income (loss) to average net assets	0.37 %	0.19 %	0.12 %	(0.14 )%	0.01 %
Portfolio turnover rate (c)	98 %	94 %	88 %	103 %	107 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

190

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$61.85	$53.68	$59.52	$39.13	$42.49
Income from investment operations:
Net investment income (loss)	0.53 (a)	0.45 (a)	0.42	0.33	0.58
Net realized and unrealized gain (loss)	11.31	8.18	(5.87 )	20.42	(3.29 )
Total from investment operations	11.84	8.63	(5.45 )	20.75	(2.71 )
Distributions paid to shareholders from:
Net investment income	(0.54 )	(0.46 )	(0.39 )	(0.36 )	(0.65 )
Net asset value, end of period	$73.15	$61.85	$53.68	$59.52	$39.13
Total Return (b)	19.26 %	16.23 %	(9.16 )%	53.21 %	(6.30 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,945,865	$1,762,616	$1,578,226	$1,767,604	$179,979
Ratio of total expenses to average net assets	0.60 %	0.61 %	0.61 %	0.61 %	0.64 %
Ratio of net investment income (loss) to average net assets	0.82 %	0.82 %	0.74 %	0.55 %	1.30 %
Portfolio turnover rate (c)	78 %	81 %	77 %	91 %	97 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

191

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Materials AlphaDEX® Fund (FXZ) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$68.14	$61.97	$57.91	$35.85	$38.48
Income from investment operations:
Net investment income (loss)	1.02 (a)	1.00 (a)	0.89	0.72	0.71
Net realized and unrealized gain (loss)	(0.89 )	6.50	3.93 (b)	22.05	(2.57 )
Total from investment operations	0.13	7.50	4.82	22.77	(1.86 )
Distributions paid to shareholders from:
Net investment income	(1.04 )	(1.33 )	(0.76 )	(0.71 )	(0.77 )
Net asset value, end of period	$67.23	$68.14	$61.97	$57.91	$35.85
Total Return (c)	0.21 %	12.41 %	8.37 %	64.02 %	(4.78 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$379,864	$589,445	$1,567,915	$460,362	$96,795
Ratio of total expenses to average net assets	0.61 %	0.62 %	0.61 %	0.64 %	0.67 %
Ratio of net investment income (loss) to average net assets	1.54 %	1.58 %	1.69 %	1.39 %	1.95 %
Portfolio turnover rate (d)	53 %	35 %	60 %	77 %	84 %

(a)

Based on average shares outstanding.

(b)

The per share amount does not correlate with the aggregate realized and unrealized gain (loss) due to the timing of the Fund share sales and repurchases in relation to market value fluctuation of the underlying investments.

(c)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(d)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

192

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Technology AlphaDEX® Fund (FXL) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$120.05	$104.35	$125.53	$89.44	$69.32
Income from investment operations:
Net investment income (loss)	0.40 (a)	0.23 (a)	0.34	(0.06 )	0.11
Net realized and unrealized gain (loss)	15.10	15.73	(21.21 )	36.15	20.17
Total from investment operations	15.50	15.96	(20.87 )	36.09	20.28
Distributions paid to shareholders from:
Net investment income	(0.40 )	(0.26 )	(0.31 )	—	(0.16 )
Net asset value, end of period	$135.15	$120.05	$104.35	$125.53	$89.44
Total Return (b)	12.93 %	15.36 %	(16.64 )%	40.34 %	29.33 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,338,637	$1,231,083	$1,143,164	$2,668,074	$2,205,109
Ratio of total expenses to average net assets	0.60 %	0.62 %	0.61 %	0.61 %	0.61 %
Ratio of net investment income (loss) to average net assets	0.32 %	0.23 %	0.27 %	(0.05 )%	0.16 %
Portfolio turnover rate (c)	119 %	104 %	91 %	92 %	110 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

193

First Trust Exchange-Traded AlphaDEX® Fund
Sector Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Utilities AlphaDEX® Fund (FXU) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$32.56	$34.33	$30.82	$27.54	$28.87
Income from investment operations:
Net investment income (loss)	0.87 (a)	0.70 (a)	0.69	0.68	1.05
Net realized and unrealized gain (loss)	2.32	(1.75 )	3.47	3.32	(1.29 )
Total from investment operations	3.19	(1.05 )	4.16	4.00	(0.24 )
Distributions paid to shareholders from:
Net investment income	(0.91 )	(0.72 )	(0.65 )	(0.72 )	(1.09 )
Net asset value, end of period	$34.84	$32.56	$34.33	$30.82	$27.54
Total Return (b)	10.15 %	(3.01 )%	13.69 %	14.80 %	(0.70 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$252,591	$306,069	$396,558	$174,146	$229,988
Ratio of total expenses to average net assets	0.63 %	0.64 %	0.64 %	0.64 %	0.62 %
Ratio of net investment income (loss) to average net assets	2.78 %	2.13 %	2.22 %	2.33 %	2.42 %
Portfolio turnover rate (c)	53 %	46 %	48 %	38 %	64 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

194

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Large Cap Core AlphaDEX® Fund (FEX) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$87.55	$81.83	$86.85	$62.29	$62.11
Income from investment operations:
Net investment income (loss)	1.18 (a)	1.35 (a)	1.01	0.71	0.93
Net realized and unrealized gain (loss)	12.60	5.74	(5.08 )	24.55	0.20
Total from investment operations	13.78	7.09	(4.07 )	25.26	1.13
Distributions paid to shareholders from:
Net investment income	(1.17 )	(1.37 )	(0.95 )	(0.70 )	(0.95 )
Net asset value, end of period	$100.16	$87.55	$81.83	$86.85	$62.29
Total Return (b)	15.89 %	8.86 %	(4.73 )%	40.77 %	1.95 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,242,042	$1,181,943	$1,104,730	$1,189,909	$924,980
Ratio of total expenses to average net assets	0.58 %	0.60 %	0.59 %	0.59 %	0.59 %
Ratio of net investment income (loss) to average net assets	1.30 %	1.67 %	1.16 %	0.94 %	1.49 %
Portfolio turnover rate (c)	88 %	87 %	87 %	91 %	104 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

195

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Large Cap Growth AlphaDEX® Fund (FTC) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$104.13	$96.84	$112.65	$82.09	$71.35
Income from investment operations:
Net investment income (loss)	0.37 (a)	0.93 (a)	0.37	(0.07 )	0.55
Net realized and unrealized gain (loss)	19.25	7.36	(15.96 )	30.67	10.80
Total from investment operations	19.62	8.29	(15.59 )	30.60	11.35
Distributions paid to shareholders from:
Net investment income	(0.40 )	(1.00 )	(0.22 )	(0.04 )	(0.61 )
Net asset value, end of period	$123.35	$104.13	$96.84	$112.65	$82.09
Total Return (b)	18.89 %	8.71 %	(13.84 )%	37.30 %	16.10 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,104,024	$1,036,129	$929,704	$1,194,111	$989,147
Ratio of total expenses to average net assets	0.58 %	0.60 %	0.59 %	0.59 %	0.60 %
Ratio of net investment income (loss) to average net assets	0.33 %	0.98 %	0.32 %	(0.07 )%	0.76 %
Portfolio turnover rate (c)	116 %	127 %	121 %	116 %	138 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

196

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Large Cap Value AlphaDEX® Fund (FTA) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$70.36	$66.10	$65.80	$46.39	$52.79
Income from investment operations:
Net investment income (loss)	1.54 (a)	1.50 (a)	1.21	1.01	1.11
Net realized and unrealized gain (loss)	7.29	4.22	0.27 (b)	19.41	(6.28 )
Total from investment operations	8.83	5.72	1.48	20.42	(5.17 )
Distributions paid to shareholders from:
Net investment income	(1.54 )	(1.46 )	(1.18 )	(1.01 )	(1.23 )
Net asset value, end of period	$77.65	$70.36	$66.10	$65.80	$46.39
Total Return (c)	12.79 %	8.90 %	2.24 %	44.43 %	(9.84 )%
Ratios to average net assets /supplemental data:
Net assets, end of period (in 000’s)	$1,223,065	$1,252,398	$1,160,039	$1,065,981	$617,016
Ratio of total expenses to average net assets	0.58 %	0.60 %	0.59 %	0.59 %	0.60 %
Ratio of net investment income (loss) to average net assets	2.19 %	2.27 %	1.79 %	1.76 %	2.12 %
Portfolio turnover rate (d)	81 %	80 %	75 %	91 %	94 %

(a)

Based on average shares outstanding.

(b)

The per share amount does not correlate with the aggregate realized and unrealized gain (loss) due to the timing of the Fund share sales and repurchases in relation to market value fluctuation of the underlying investments.

(c)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(d)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

197

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Mid Cap Core AlphaDEX® Fund (FNX) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$101.01	$92.46	$99.26	$64.83	$69.86
Income from investment operations:
Net investment income (loss)	1.13 (a)	1.11 (a)	1.08	0.70	0.85
Net realized and unrealized gain (loss)	15.17	8.60	(6.74 )	34.51	(4.93 )
Total from investment operations	16.30	9.71	(5.66 )	35.21	(4.08 )
Distributions paid to shareholders from:
Net investment income	(1.19 )	(1.16 )	(1.14 )	(0.78 )	(0.95 )
Net asset value, end of period	$116.12	$101.01	$92.46	$99.26	$64.83
Total Return (b)	16.28 %	10.70 %	(5.74 )%	54.62 %	(5.86 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$1,225,117	$1,080,834	$975,495	$1,027,303	$589,912
Ratio of total expenses to average net assets	0.58 %	0.60 %	0.59 %	0.59 %	0.60 %
Ratio of net investment income (loss) to average net assets	1.11 %	1.22 %	1.12 %	0.79 %	1.32 %
Portfolio turnover rate (c)	103 %	106 %	95 %	114 %	115 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

198

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Mid Cap Growth AlphaDEX® Fund (FNY) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$66.68	$61.22	$73.58	$51.23	$46.59
Income from investment operations:
Net investment income (loss)	0.05 (a)	0.21 (a)	0.01	(0.18 )	0.11
Net realized and unrealized gain (loss)	9.95	5.49	(12.37 )	22.69	4.67
Total from investment operations	10.00	5.70	(12.36 )	22.51	4.78
Distributions paid to shareholders from:
Net investment income	(0.06 )	(0.24 )	- —	(0.16 )	(0.14 )
Net asset value, end of period	$76.62	$66.68	$61.22	$73.58	$51.23
Total Return (b)	15.01 %	9.37 %	(16.80 )%	44.02 %	10.28 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$348,628	$276,716	$281,629	$463,572	$338,149
Ratio of total expenses to average net assets	0.70 %	0.70 %	0.70 %	0.70 %	0.70 %
Ratio of net investment income (loss) to average net assets	0.07 %	0.35 %	0.09 %	(0.24 )%	0.23 %
Portfolio turnover rate (c)	134 %	142 %	136 %	138 %	135 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

199

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Mid Cap Value AlphaDEX® Fund (FNK) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$49.00	$44.58	$44.69	$27.71	$34.67
Income from investment operations:
Net investment income (loss)	0.88 (a)	0.78 (a)	0.74	0.54	0.63
Net realized and unrealized gain (loss)	6.69	4.42	(0.16 )	16.98	(6.86 )
Total from investment operations	7.57	5.20	0.58	17.52	(6.23 )
Distributions paid to shareholders from:
Net investment income	(0.89 )	(0.78 )	(0.69 )	(0.54 )	(0.73 )
Net asset value, end of period	$55.68	$49.00	$44.58	$44.69	$27.71
Total Return (b)	15.68 %	11.95 %	1.31 %	63.76 %	(18.19 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$228,290	$237,648	$222,894	$140,774	$34,636
Ratio of total expenses to average net assets	0.70 %	0.70 %	0.70 %	0.70 %	0.70 %
Ratio of net investment income (loss) to average net assets	1.79 %	1.77 %	1.63 %	1.33 %	2.04 %
Portfolio turnover rate (c)	98 %	102 %	84 %	102 %	107 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

200

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Multi Cap Growth AlphaDEX® Fund (FAD) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$109.30	$101.49	$119.58	$83.11	$75.90
Income from investment operations:
Net investment income (loss)	0.31 (a)	0.72 (a)	0.46	(0.11 )	0.42
Net realized and unrealized gain (loss)	17.64	7.81	(18.27 )	36.71	7.27
Total from investment operations	17.95	8.53	(17.81 )	36.60	7.69
Distributions paid to shareholders from:
Net investment income	(0.31 )	(0.72 )	(0.28 )	(0.13 )	(0.48 )
Net asset value, end of period	$126.94	$109.30	$101.49	$119.58	$83.11
Total Return (b)	16.47 %	8.50 %	(14.91 )%	44.10 %	10.23 %
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$209,445	$180,346	$182,686	$221,229	$170,367
Ratio of total expenses to average net assets	0.62 %	0.64 %	0.63 %	0.63 %	0.63 %
Ratio of net investment income (loss) to average net assets	0.28 %	0.72 %	0.39 %	(0.09 )%	0.56 %
Portfolio turnover rate (c)	115 %	125 %	115 %	104 %	123 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

201

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Multi Cap Value AlphaDEX® Fund (FAB) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$75.69	$70.76	$71.04	$46.72	$54.39
Income from investment operations:
Net investment income (loss)	1.52 (a)	1.38 (a)	1.20	0.84	0.95
Net realized and unrealized gain (loss)	9.47	4.94	(0.35 )	24.34	(7.54 )
Total from investment operations	10.99	6.32	0.85	25.18	(6.59 )
Distributions paid to shareholders from:
Net investment income	(1.54 )	(1.39 )	(1.13 )	(0.86 )	(1.08 )
Net asset value, end of period	$85.14	$75.69	$70.76	$71.04	$46.72
Total Return (b)	14.76 %	9.19 %	1.20 %	54.35 %	(12.24 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$148,991	$174,084	$176,894	$166,942	$51,387
Ratio of total expenses to average net assets	0.64 %	0.64 %	0.66 %	0.69 %	0.74 %
Ratio of net expenses to average net assets	0.64 %	0.64 %	0.66 %	0.69 %	0.70 %
Ratio of net investment income (loss) to average net assets	2.01 %	1.96 %	1.64 %	1.43 %	1.86 %
Portfolio turnover rate (c)	87 %	85 %	76 %	92 %	98 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year. The total returns would have been lower if certain fees had not been waived and expenses reimbursed by the investment advisor.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

202

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Small Cap Core AlphaDEX® Fund (FYX) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$88.60	$84.49	$91.31	$55.98	$61.84
Income from investment operations:
Net investment income (loss)	1.11 (a)	0.95 (a)	1.05	0.61	0.51
Net realized and unrealized gain (loss)	11.57	4.13	(6.92 )	35.35	(5.75 )
Total from investment operations	12.68	5.08	(5.87 )	35.96	(5.24 )
Distributions paid to shareholders from:
Net investment income	(1.12 )	(0.97 )	(0.95 )	(0.63 )	(0.62 )
Net asset value, end of period	$100.16	$88.60	$84.49	$91.31	$55.98
Total Return (b)	14.47 %	6.16 %	(6.50 )%	64.45 %	(8.55 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$931,477	$872,703	$827,993	$917,700	$397,470
Ratio of total expenses to average net assets	0.59 %	0.60 %	0.59 %	0.60 %	0.61 %
Ratio of net investment income (loss) to average net assets	1.27 %	1.17 %	1.18 %	0.77 %	0.93 %
Portfolio turnover rate (c)	112 %	109 %	94 %	116 %	123 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

203

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Small Cap Growth AlphaDEX® Fund (FYC) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$63.92	$60.22	$71.14	$44.46	$46.87
Income from investment operations:
Net investment income (loss)	0.23 (a)	0.36 (a)	0.54	0.03	0.17
Net realized and unrealized gain (loss)	7.34	3.47	(10.99 )	26.72	(2.40 )
Total from investment operations	7.57	3.83	(10.45 )	26.75	(2.23 )
Distributions paid to shareholders from:
Net investment income	(0.30 )	(0.13 )	(0.47 )	(0.07 )	(0.18 )
Net asset value, end of period	$71.19	$63.92	$60.22	$71.14	$44.46
Total Return (b)	11.92 %	6.38 %	(14.81 )%	60.24 %	(4.79 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$295,446	$230,119	$201,727	$394,827	$146,704
Ratio of total expenses to average net assets	0.70 %	0.70 %	0.70 %	0.70 %	0.70 %
Ratio of net investment income (loss) to average net assets	0.37 %	0.62 %	0.88 %	0.02 %	0.44 %
Portfolio turnover rate (c)	141 %	140 %	132 %	151 %	137 %

(a)

Based on average shares outstanding.

(b)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(c)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

204

First Trust Exchange-Traded AlphaDEX® Fund
Style Funds

Financial Highlights
For a share outstanding throughout each period

First Trust Small Cap Value AlphaDEX® Fund (FYT) 

	Year Ended July 31,
	2024	2023	2022	2021	2020
Net asset value, beginning of period	$50.47	$48.64	$50.28	$30.78	$34.66
Income from investment operations:
Net investment income (loss)	0.87 (a)	0.66 (a)	0.67	0.45	0.38
Net realized and unrealized gain (loss)	7.95	1.96 (b)	(1.69 )	19.52	(3.75 )
Total from investment operations	8.82	2.62	(1.02 )	19.97	(3.37 )
Distributions paid to shareholders from:
Net investment income	(0.80 )	(0.79 )	(0.62 )	(0.47 )	(0.51 )
Net asset value, end of period	$58.49	$50.47	$48.64	$50.28	$30.78
Total Return (c)	17.68 %	5.61 %	(2.06 )%	65.22 %	(9.83 )%
Ratios to average net assets/supplemental data:
Net assets, end of period (in 000’s)	$187,166	$174,136	$223,722	$268,991	$46,176
Ratio of total expenses to average net assets	0.70 %	0.70 %	0.70 %	0.70 %	0.70 %
Ratio of net investment income (loss) to average net assets	1.71 %	1.42 %	1.29 %	1.08 %	1.18 %
Portfolio turnover rate (d)	114 %	110 %	90 %	109 %	120 %

(a)

Based on average shares outstanding.

(b)

The per share amount does not correlate with the aggregate realized and unrealized gain (loss) due to the timing of the Fund share sales and repurchases in relation to market value fluctuation of the underlying investments.

(c)

Total return is calculated assuming an initial investment made at the net asset value at the beginning of the period, reinvestment of all distributions at net asset value during the period, and redemption at net asset value on the last day of the period. The returns presented do not reflect the deduction of taxes that a shareholder would pay on Fund distributions or the redemption or sale of Fund shares. Total return is calculated for the time period presented and is not annualized for periods of less than a year.

(d)

Portfolio turnover is calculated for the time period presented and is not annualized for periods of less than a year and does not include securities received or delivered from processing creations or redemptions and in-kind transactions.

205

Other Information

Continuous Offering

Each Fund issues, on a continuous offering basis, its shares in one or more groups of a fixed number of Fund shares (each such group of such specified number of individual Fund shares, a “Creation Unit Aggregation”). The method by which Creation Unit Aggregations of Fund shares are created and traded may raise certain issues under applicable securities laws. Because new Creation Unit Aggregations of shares are issued and sold by a Fund on an ongoing basis, a “distribution,” as such term is used in the Securities Act, may occur at any point. Broker-dealers and other persons are cautioned that some activities on their part may, depending on the circumstances, result in their being deemed participants in a distribution in a manner which could render them statutory underwriters and subject them to the prospectus delivery requirement and liability provisions of the Securities Act.

For example, a broker-dealer firm or its client may be deemed a statutory underwriter if it takes Creation Unit Aggregations after placing an order with FTP, breaks them down into constituent shares and sells such shares directly to customers, or if it chooses to couple the creation of a supply of new shares with an active selling effort involving solicitation of secondary market demand for shares. A determination of whether one is an underwriter for purposes of the Securities Act must take into account all the facts and circumstances pertaining to the activities of the broker-dealer or its client in the particular case, and the examples mentioned above should not be considered a complete description of all the activities that could lead to a characterization as an underwriter.

Broker-dealer firms should also note that dealers who are not “underwriters” but are effecting transactions in shares, whether or not participating in the distribution of shares, are generally required to deliver a prospectus. This is because the prospectus delivery exemption in Section 4(a)(3) of the Securities Act is not available in respect of such transactions as a result of Section 24(d) of the 1940 Act. As a result, broker-dealer firms should note that dealers who are not underwriters but are participating in a distribution (as contrasted with ordinary secondary market transactions) and thus dealing with the shares that are part of an overallotment within the meaning of Section 4(a)(3)(C) of the Securities Act would be unable to take advantage of the prospectus delivery exemption provided by Section 4(a)(3) of the Securities Act. Firms that incur a prospectus delivery obligation with respect to shares are reminded that, under the Securities Act Rule 153, a prospectus delivery obligation under Section 5(b)(2) of the Securities Act owed to a broker-dealer in connection with a sale on the applicable Exchange is satisfied by the fact that the prospectus is available from the applicable Exchange upon request. The prospectus delivery mechanism provided in Rule 153 is available with respect to transactions on a national securities exchange, a trading facility or an alternative trading system.

FTP, or its affiliates, or a fund or unit investment trust for which FTP or an affiliate serves as sponsor or investment advisor, may purchase shares of a Fund through a broker-dealer or other investors, including in secondary market transactions, and because FTP or its affiliates may be deemed affiliates of such Fund, the shares are being registered to permit the resale of these shares from time to time after any such purchase. A Fund will not receive any of the proceeds from the resale of such shares.

206

  

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First Trust

Exchange-Traded AlphaDEX® Fund

 

 

 

ALPHADEX® SECTOR FUNDS

First Trust Consumer Discretionary AlphaDEX® Fund

First Trust Consumer Staples AlphaDEX® Fund

First Trust Energy AlphaDEX® Fund

First Trust Financials AlphaDEX® Fund

First Trust Health Care AlphaDEX® Fund

First Trust Industrials/Producer Durables AlphaDEX® Fund

First Trust Materials AlphaDEX® Fund

First Trust Technology AlphaDEX® Fund

Fund First Trust Utilities AlphaDEX® Fund

ALPHADEX® STYLE FUNDS

First Trust Large Cap Core AlphaDEX® Fund

First Trust Large Cap Growth AlphaDEX® Fund

First Trust Large Cap Value AlphaDEX® Fund

First Trust Mid Cap Core AlphaDEX® Fund

First Trust Mid Cap Growth AlphaDEX® Fund

First Trust Mid Cap Value AlphaDEX® Fund

First Trust Multi Cap Growth AlphaDEX® Fund

First Trust Multi Cap Value AlphaDEX® Fund

First Trust Small Cap Core AlphaDEX® Fund

First Trust Small Cap Growth AlphaDEX® Fund

First Trust Small Cap Value AlphaDEX® Fund

For More Information

For more detailed information on the Funds, several additional sources of information are available to you. The SAI, incorporated by reference into this prospectus, contains detailed information on the Funds' policies and operation. Additional information about the Funds' investments is available in the annual and semi-annual reports to shareholders and in Form N-CSR. In the Funds' annual reports, you will find a discussion of the market conditions and investment strategies that significantly impacted the Funds' performance during the last fiscal year. In Form N-CSR, you will find the Fund’s annual and semi-annual financial statements. The Funds' most recent SAI, annual and semi-annual reports and certain other information such as Fund financial statements are available free of charge by calling the Funds at (800) 621-1675, on the Funds' website at  http://www.ftportfolios.com  or through your financial advisor. Shareholders may call the toll-free number above with any inquiries.

You may obtain this and other information regarding the Funds, including the SAI and the Codes of Ethics adopted by First Trust, FTP and the Trust, directly from the Securities and Exchange Commission (the "SEC"). Information on the SEC’s website is free of charge. Visit the SEC’s online EDGAR database at  http://www.sec.gov.  You may also request information regarding the Funds by sending a request (along with a duplication fee) to the SEC by sending an electronic request to publicinfo@sec.gov.

First Trust Advisors L.P.
120 East Liberty Drive, Suite 400
Wheaton, Illinois 60187
(800) 621-1675

http://www.ftportfolios.com

SEC File #: 333-140895 811-22019

STATEMENT OF ADDITIONAL INFORMATION

Investment Company Act File No. 811-22019

First Trust Exchange-Traded AlphaDEX® Fund 

FUND NAME	TICKER SYMBOL	EXCHANGE
ALPHADEX® SECTOR FUNDS
First Trust Consumer Discretionary AlphaDEX® Fund	FXD	NYSE Arca
First Trust Consumer Staples AlphaDEX® Fund	FXG	NYSE Arca
First Trust Energy AlphaDEX® Fund	FXN	NYSE Arca
First Trust Financials AlphaDEX® Fund	FXO	NYSE Arca
First Trust Health Care AlphaDEX® Fund	FXH	NYSE Arca
First Trust Industrials/Producer Durables AlphaDEX® Fund	FXR	NYSE Arca
First Trust Materials AlphaDEX® Fund	FXZ	NYSE Arca
First Trust Technology AlphaDEX® Fund	FXL	NYSE Arca
First Trust Utilities AlphaDEX® Fund	FXU	NYSE Arca
ALPHADEX® STYLE FUNDS
First Trust Large Cap Core AlphaDEX® Fund	FEX	Nasdaq
First Trust Large Cap Growth AlphaDEX® Fund	FTC	Nasdaq
First Trust Large Cap Value AlphaDEX® Fund	FTA	Nasdaq
First Trust Mid Cap Core AlphaDEX® Fund	FNX	Nasdaq
First Trust Mid Cap Growth AlphaDEX® Fund	FNY	Nasdaq
First Trust Mid Cap Value AlphaDEX® Fund	FNK	Nasdaq
First Trust Multi Cap Growth AlphaDEX® Fund	FAD	Nasdaq
First Trust Multi Cap Value AlphaDEX® Fund	FAB	Nasdaq
First Trust Small Cap Core AlphaDEX® Fund	FYX	Nasdaq
First Trust Small Cap Growth AlphaDEX® Fund	FYC	Nasdaq
First Trust Small Cap Value AlphaDEX® Fund	FYT	Nasdaq

DATED DECEMBER 2, 2024

This Statement of Additional Information (“SAI”) is not a prospectus. It should be read in conjunction with the prospectus dated December 2, 2024, as it may be revised from time to time (the “Prospectus”), for each of the First Trust Consumer Discretionary AlphaDEX® Fund, First Trust Consumer Staples AlphaDEX® Fund, First Trust Energy AlphaDEX® Fund, First Trust Financials AlphaDEX® Fund, First Trust Health Care AlphaDEX® Fund, First Trust Industrials/Producer Durables AlphaDEX® Fund, First Trust Materials AlphaDEX® Fund, First Trust Technology AlphaDEX® Fund, First Trust Utilities AlphaDEX® Fund, First Trust Large Cap Core AlphaDEX® Fund, First Trust Large Cap Growth AlphaDEX® Fund, First Trust Large Cap Value AlphaDEX® Fund, First Trust Mid Cap Core AlphaDEX® Fund, First Trust Mid Cap Growth AlphaDEX® Fund, First Trust Mid Cap Value AlphaDEX® Fund, First Trust Multi Cap Growth AlphaDEX® Fund, First Trust Multi Cap Value AlphaDEX® Fund, First Trust Small Cap Core AlphaDEX® Fund, First Trust Small Cap Growth AlphaDEX® Fund and First Trust Small Cap Value AlphaDEX® Fund (each, a “Fund” and collectively, the “Funds”), each a series of the First Trust Exchange-Traded AlphaDEX® Fund (the “Trust”). Capitalized terms used herein that are not defined have the same meaning as in the Prospectus, unless otherwise noted. A copy of the Prospectus may be obtained without charge by writing to the Trust’s distributor, First Trust Portfolios L.P., 120 East Liberty Drive, Suite 400, Wheaton, Illinois 60187, or by calling toll free at (800) 621-1675.

The audited financial statements for the Funds' most recent fiscal year appear in the Funds' Form N-CSR dated July 31, 2024, which was filed with the Securities and Exchange Commission (the “SEC”) on October 8, 2024. The financial statements from the Form N-CSR are incorporated herein by reference. The Form N-CSR is available without charge by calling (800) 621-1675 or by visiting the SEC’s website at http://www.sec.gov.

Table of Contents 

General Description of the Trust and the Funds	1
Exchange Listing and Trading	3
Investment Objectives and Policies	3
Investment Strategies	4
Sublicense Agreements	15
Investment Risks	15
Management of the Funds	19
Accounts Managed by Investment Committee	31
Brokerage Allocations	31
Administrator, Fund Accounting Agent, Custodian, Transfer Agent, Distributor, Index Providers and Exchanges	33
Additional Payments to Financial Intermediaries	37
Additional Information	38
Proxy Voting Policies and Procedures	43
Creation and Redemption of Creation Units	44
Federal Tax Matters	47
Determination of Net Asset Value	52
Dividends and Distributions	52
Miscellaneous Information	53
Financial Statements	53
Exhibit A—Principal Holders Table	A-1
Exhibit B—Proxy Voting Policies and Procedures	B-1

i

General Description of the Trust and the Funds

The Trust was organized as a Massachusetts business trust on December 6, 2006 and is authorized to issue an unlimited number of shares in one or more series. The Trust is an open-end management investment company, registered under the Investment Company Act of 1940, as amended (the “1940 Act”). The Trust currently offers shares in 20 series. This SAI relates to the Funds, which are diversified series.

Each Fund, as a series of the Trust, represents a beneficial interest in a separate portfolio of securities and other assets, with its own objective and policies.

The Board of Trustees of the Trust (the “Board,”  “Board of Trustees” or “Trustees”) has the right to establish additional series in the future, to determine the preferences, voting powers, rights and privileges thereof and to modify such preferences, voting powers, rights and privileges without shareholder approval. Shares of any series may also be divided into one or more classes at the discretion of the Trustees.

The Trust or any series or class thereof may be terminated at any time by the Board of Trustees upon written notice to the shareholders.

Each share has one vote with respect to matters upon which a shareholder vote is required consistent with the requirements of the 1940 Act and the rules promulgated thereunder. Shares of all series of the Trust vote together as a single class except as otherwise required by the 1940 Act or if the matter being voted on affects only a particular series, and, if a matter affects a particular series differently from other series, the shares of that series will vote separately on such matter. The Trust’s Declaration of Trust (the “Declaration”) requires a shareholder vote only on those matters where the 1940 Act requires a vote of shareholders and otherwise permits the Trustees to take actions without seeking the consent of shareholders. For example, the Declaration gives the Trustees broad authority to approve reorganizations between a Fund and another entity, such as another exchange-traded fund, or the sale of all or substantially all of a Fund's assets, or the termination of the Trust or any Fund without shareholder approval if the 1940 Act would not require such approval.

The Declaration provides that by becoming a shareholder of a Fund, each shareholder shall be expressly held to have agreed to be bound by the provisions of the Declaration and to any By-laws adopted by the Trust. The Declaration provides that, except as set forth therein and authorized by the Trustees, shareholders have no rights, privileges, claims or remedies under any contract or agreement entered into by the Trust or a Fund with any service provider or other agent to or contractor with the Trust or a Fund including, without limitation, any third party beneficiary rights.

The Declaration may, except in limited circumstances, be amended by the Trustees in any respect without a shareholder vote. The Declaration provides that the Trustees may establish the number of Trustees and that vacancies on the Board of Trustees may be filled by the remaining Trustees, except when election of Trustees by the shareholders is required under the 1940 Act. Trustees are then elected by a plurality of votes cast by shareholders at a meeting at which a quorum is present. The Declaration also provides that Trustees may be removed, with or without cause, by a vote of shareholders holding at least two-thirds of the voting power of the Trust, or by a vote of two-thirds of the remaining Trustees. The provisions of the Declaration relating to the election and removal of Trustees may not be amended without the approval of two-thirds of the Trustees.

The holders of Fund shares are required to disclose information on direct or indirect ownership of Fund shares as may be required to comply with various laws applicable to the Funds or as the Trustees may determine, and ownership of Fund shares may be disclosed by the Funds if so required by law or regulation. In addition, pursuant to the Declaration, the Trustees may, in their discretion, require the Trust to redeem shares held by any shareholder for any reason under terms set by the Trustees.

The Declaration provides a detailed process for the bringing of derivative actions by shareholders in order to permit legitimate inquiries and claims while avoiding the time, expense, distraction and other harm that can be caused to a Fund or its shareholders as a result of spurious shareholder demands and derivative actions. In addition, the Declaration provides that actions that are derivative in nature may not be brought directly. Prior to bringing a derivative action, a demand must first be made on the Trustees. The Declaration details various information, certifications, undertakings and acknowledgements that must be included in the demand. Following receipt of the demand, the Trustees have a period of 90 days, which may be extended by an additional 60 days, to consider the demand. If a majority of the Trustees who are considered independent for the purposes of considering the demand determine that maintaining the suit would not be in the best interests of the Funds, the Trustees are required to reject the demand and the complaining shareholder may not proceed with the derivative action unless the shareholder is able to sustain the burden of proof to a court that the decision

1

of the Trustees not to pursue the requested action was not a good faith exercise of their business judgment on behalf of the Funds. In making such a determination, a Trustee is not considered to have a personal financial interest by virtue of being compensated for his or her services as a Trustee. If a demand is rejected, the complaining shareholder will be responsible for the costs and expenses (including attorneys’ fees) incurred by the Funds in connection with the consideration of the demand under a number of circumstances. In addition, if a court determines that a derivative action was made without reasonable cause or for an improper purpose, or if a derivative or direct action is dismissed on the basis of a failure to comply with the procedural provisions relating to shareholder actions as set forth in the Declaration, or if a direct action is dismissed by a court for failure to state a claim, the shareholder bringing the action may be responsible for a Fund's costs, including attorneys’ fees.

The provisions of the Declaration provide that any direct or derivative action commenced by a shareholder must be brought only in the U.S. District Court for the District of Massachusetts (Boston Division) or if any such action may not be brought in that court, then in the Business Litigation Session of Suffolk Superior Court in Massachusetts (the “Chosen Courts”). Except as prohibited by applicable law, if a shareholder commences an applicable action in a court other than a Chosen Court without the consent of a Fund, then such shareholder may be obligated to reimburse the Fund and any applicable Trustee or officer of the Fund made party to such proceeding for the costs and expenses (including attorneys’ fees) incurred in connection with any successful motion to dismiss, stay or transfer of the action. The Declaration also provides that any shareholder bringing an action against a Fund waives the right to trial by jury to the fullest extent permitted by law.

The Trust is not required to and does not intend to hold annual meetings of shareholders.

Under Massachusetts law applicable to Massachusetts business trusts, shareholders of such a trust may, under certain circumstances, be held personally liable as partners for its obligations. However, the Declaration contains an express disclaimer of shareholder liability for acts or obligations of the Trust and requires that notice of this disclaimer be given in each agreement, obligation or instrument entered into or executed by the Trust or the Trustees. The Declaration further provides for indemnification out of the assets and property of the Trust for all losses and expenses of any shareholder held personally liable for the obligations of the Trust. Thus, the risk of a shareholder incurring financial loss on account of shareholder liability is limited to circumstances in which both inadequate insurance existed and the Trust or a Fund itself was unable to meet its obligations.

The Declaration provides that a Trustee acting in his or her capacity as Trustee is liable to the Trust for his or her own bad faith, willful misfeasance, gross negligence, or reckless disregard of his or her duties involved in the conduct of the individual’s office, and for nothing else and shall not be liable for errors of judgment or mistakes of fact or law. The Declaration also provides that the Trustees of the Trust will be subject to the laws of the Commonwealth of Massachusetts relating to Massachusetts business trusts, but not to the laws of Massachusetts relating to the trustees of common law trusts, such as donative or probate type trusts. The Declaration further provides that a Trustee acting in his or her capacity as Trustee is not personally liable to any person other than the Trust, for any act, omission, or obligation of the Trust. The Declaration requires the Trust to indemnify any persons who are or who have been Trustees, officers or employees of the Trust for any liability for actions or failure to act except to the extent prohibited by applicable federal law. In making any determination as to whether any person is entitled to the advancement of expenses in connection with a claim for which indemnification is sought, such person is entitled to a rebuttable presumption that he or she did not engage in conduct for which indemnification is not available. The Declaration provides that any Trustee who serves as chair of the Board of Trustees or of a committee of the Board of Trustees, as lead independent Trustee or as audit committee financial expert, or in any other similar capacity will not be subject to any greater standard of care or liability because of such position.

These provisions are not intended to restrict any shareholder rights under the federal securities laws and the Declaration specifically provides that no provision of the Declaration shall be effective to require a waiver of compliance with any provision of, or restrict any shareholder rights expressly granted by, the Securities Act of 1933, as amended (the “1933 Act”), the Securities Exchange Act of 1934, as amended (the “1934 Act”) or the 1940 Act, or any valid rule, regulation or order of the Securities Exchange Commission thereunder.

The Funds are advised by First Trust Advisors L.P. (the “Advisor” or “First Trust”).

The shares of each Fund are principally listed and traded on NYSE Arca, Inc., (“NYSE Arca”) or Nasdaq, Inc. (“Nasdaq"), (each an “Exchange”), as shown on the cover of this SAI. ETFs, such as the Funds, do not sell or redeem individual shares of a Fund. Instead, financial entities known as “Authorized Participants” (which are discussed in greater detail below) have contractual arrangements with each Fund or the Distributor to purchase and redeem Fund shares directly with a Fund

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in large blocks of shares known as “Creation Units.” An Authorized Participant that purchases a Creation Unit of Fund shares deposits with a Fund a “basket” of securities, cash and/or other assets identified by the Fund that day, and then receives the Creation Unit of Fund shares in return for those assets. The redemption process is the reverse of the purchase process: the Authorized Participant redeems a Creation Unit of Fund shares for a basket of securities, cash and/or other assets. The basket is generally representative of a Fund’s portfolio, and together with a cash balancing amount, it is equal to the NAV of the Fund shares comprising the Creation Unit. Pursuant to Rule 6c-11 of the 1940 Act, the Funds may utilize baskets that are not representative of each Fund’s portfolio. Such “custom baskets” are discussed in the section entitled “Creation and Redemption of Creation Units.”

Fund shares may be issued in advance of receipt of deposit securities subject to various conditions including a requirement to maintain on deposit with the applicable Fund cash at least equal to 115% of the market value of the missing deposit securities. See the section entitled “Creation and Redemption of Creation Units.” In each instance of such cash creations or redemptions, transaction fees may be imposed that will be higher than the transaction fees associated with in-kind creations or redemptions. In all cases, such fees will be limited in accordance with the requirements of the SEC applicable to management investment companies offering redeemable securities.

Exchange Listing and Trading

There can be no assurance that the requirements of an Exchange necessary to maintain the listing of shares of a Fund will continue to be met. An Exchange may, but is not required to, remove the shares of a Fund from listing if (i) following the initial 12-month period beginning at the commencement of trading of a Fund, there are fewer than 50 beneficial owners of the shares of such Fund for 30 or more consecutive trading days; (ii) the value of such Fund’s Index (as defined below) is no longer calculated or available; or (iii) such other event shall occur or condition exist that, in the opinion of an Exchange, makes further dealings on an Exchange inadvisable. Please note that NYSE Arca may have a conflict of interest with respect to the AlphaDEX® Sector Funds because the shares of such Funds are listed on NYSE Arca and NYSE Arca is an affiliate of ICE Data Indices, LLC (“IDI” or an “Index Provider”), the Index Provider of the AlphaDEX® Sector Funds. Additionally, Nasdaq may have a conflict of interest with respect to the AlphaDEX® Style Funds because the shares of such Funds are listed on Nasdaq and Nasdaq, along with IDI (the "Index Providers") are the Index Providers of the AlphaDEX® Style Funds. An Exchange will remove the shares of a Fund from listing and trading upon termination of such Fund.

As in the case of other stocks traded on an Exchange, brokers’ commissions on transactions will be based on negotiated commission rates at customary levels.

The Funds reserve the right to adjust the price levels of shares in the future to help maintain convenient trading ranges for investors. Any adjustments would be accomplished through stock splits or reverse stock splits, which would have no effect on the net assets of each Fund.

Investment Objectives and Policies

The Prospectus describes the investment objectives and certain policies of the Funds. The following supplements the information contained in the Prospectus concerning the investment objectives and policies of the Funds.

Each Fund is subject to the following fundamental policies, which may not be changed without approval of the holders of a majority of the outstanding voting securities (as such term is defined in the 1940 Act) of a Fund:

(1)

A Fund may not issue senior securities, except as permitted under the 1940 Act.

(2)

A Fund may not borrow money, except that a Fund may (i) borrow money from banks for temporary or emergency purposes (but not for leverage or the purchase of investments) and (ii) engage in other transactions permissible under the 1940 Act that may involve a borrowing (such as obtaining short-term credits as are necessary for the clearance of transactions, engaging in delayed-delivery transactions, or purchasing certain futures, forward contracts and options), provided that the combination of (i) and (ii) shall not exceed 33⅓% of the value of a Fund's total assets (including the amount borrowed), less a Fund's liabilities (other than borrowings).

(3)

A Fund will not underwrite the securities of other issuers except to the extent a Fund may be considered an underwriter under the 1933 Act, in connection with the purchase and sale of portfolio securities.

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(4)

A Fund will not purchase or sell real estate or interests therein, unless acquired as a result of ownership of securities or other instruments (but this shall not prohibit a Fund from purchasing or selling securities or other instruments backed by real estate or of issuers engaged in real estate activities).

(5)

A Fund may not make loans to other persons, except through (i) the purchase of debt securities permissible under a Fund’s investment policies, (ii) repurchase agreements, or (iii) the lending of portfolio securities, provided that no such loan of portfolio securities may be made by a Fund if, as a result, the aggregate of such loans would exceed 33⅓% of the value of a Fund’s total assets.

(6)

A Fund may not purchase or sell physical commodities unless acquired as a result of ownership of securities or other instruments (but this shall not prevent a Fund from purchasing or selling options, futures contracts, forward contracts or other derivative instruments, or from investing in securities or other instruments backed by physical commodities).

(7)

A Fund may not invest 25% or more of the value of its total assets in securities of issuers in any one industry or group of industries, except to the extent that the Fund’s Index is based on concentrations in an industry or a group of industries. This restriction does not apply to obligations issued or guaranteed by the U.S. government, its agencies or instrumentalities.

For purposes of applying restriction (1) above, under the 1940 Act as currently in effect, the Funds are not permitted to issue senior securities, except that a Fund may borrow from any bank if, immediately after such borrowing, the value of such Fund’s total assets is at least 300% of the principal amount of all of a Fund’s borrowings (i.e., the principal amount of the borrowings may not exceed 33⅓% of a Fund's total assets). In the event that such asset coverage shall at any time fall below 300% the applicable Fund shall, within three days thereafter (not including Sundays and holidays), reduce the amount of its borrowings to an extent that the asset coverage of such borrowings shall be at least 300%.

Except for restriction (2) above, if a percentage restriction is adhered to at the time of investment, a later increase in percentage resulting from a change in market value of the investment or the total assets will not constitute a violation of that restriction. With respect to restriction (2), if the limitations are exceeded as a result of a change in market value then the Fund will reduce the amount of borrowings within three days thereafter to the extent necessary to comply with the limitations (not including Sundays and holidays).

The fundamental investment limitations set forth above limit the Funds' ability to engage in certain investment practices and purchase securities or other instruments to the extent permitted by, or consistent with, applicable law. As such, these limitations will change as the statute, rules, regulations or orders (or, if applicable, interpretations) change, and no shareholder vote will be required or sought.

The foregoing fundamental policies of each Fund may not be changed without the affirmative vote of the majority of the outstanding voting securities of the respective Fund. The 1940 Act defines a majority vote as the vote of the lesser of (i) 67% or more of the voting securities represented at a meeting at which more than 50% of the outstanding securities are represented; or (ii) more than 50% of the outstanding voting securities. With respect to the submission of a change in an investment policy to the holders of outstanding voting securities of a Fund, such matter shall be deemed to have been effectively acted upon with respect to a Fund if a majority of the outstanding voting securities of a Fund vote for the approval of such matter, notwithstanding that such matter has not been approved by the holders of a majority of the outstanding voting securities of any other series of the Trust affected by such matter.

In addition to the foregoing fundamental policies, the Funds are also subject to strategies and policies discussed herein which, unless otherwise noted, are non-fundamental restrictions and policies and may be changed by the Board of Trustees.

Investment Strategies

The following information supplements the discussion of each Fund’s investment objective, policies and strategies that appears in the Prospectus.

Under normal circumstances, each Fund will invest at least 90% of its net assets (including any investment borrowings) in the securities that comprise the index it seeks to track (each, an “Index” and collectively, the “Indices”).  Fund shareholders are entitled to 60 days’ notice prior to any change in this non-fundamental investment policy.

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The Indices in the following table (the “StrataQuant® Series”) are a family of custom “enhanced” indices developed, maintained and owned by IDI and licensed to First Trust Portfolios L.P. (“FTP” or the “Distributor”) by IDI. IDI is a successor-in-interest to previous entities that maintained the Indices as part of NYSE Group, Inc. and American Stock Exchange LLC. 

Fund	Index
First Trust Consumer Discretionary AlphaDEX® Fund	StrataQuant® Consumer Discretionary Index
First Trust Consumer Staples AlphaDEX® Fund	StrataQuant® Consumer Staples Index
First Trust Energy AlphaDEX® Fund	StrataQuant® Energy Index
First Trust Financials AlphaDEX® Fund	StrataQuant® Financials Index
First Trust Health Care AlphaDEX® Fund	StrataQuant® Health Care Index
First Trust Industrials/Producer Durables AlphaDEX® Fund	StrataQuant® Industrials Index
First Trust Materials AlphaDEX® Fund	StrataQuant® Materials Index
First Trust Technology AlphaDEX® Fund	StrataQuant® Technology Index
First Trust Utilities AlphaDEX® Fund	StrataQuant® Utilities Index

The Indices in the following table are a family of custom “enhanced” indices developed, maintained and sponsored by Nasdaq, Inc. and licensed to FTP by Nasdaq, Inc. 

Fund	Index
First Trust Large Cap Core AlphaDEX® Fund	Nasdaq AlphaDEX Large Cap CoreTM Index
First Trust Large Cap Growth AlphaDEX® Fund	Nasdaq AlphaDEX Large Cap GrowthTM Index
First Trust Large Cap Value AlphaDEX® Fund	Nasdaq AlphaDEX Large Cap ValueTM Index
First Trust Mid Cap Core AlphaDEX® Fund	Nasdaq AlphaDEX Mid Cap CoreTM Index
First Trust Mid Cap Growth AlphaDEX® Fund	Nasdaq AlphaDEX Mid Cap GrowthTM Index
First Trust Mid Cap Value AlphaDEX® Fund	Nasdaq AlphaDEX Mid Cap ValueTM Index
First Trust Multi Cap Growth AlphaDEX® Fund	Nasdaq AlphaDEX Multi Cap GrowthTM Index
First Trust Multi Cap Value AlphaDEX® Fund	Nasdaq AlphaDEX Multi Cap ValueTM Index
First Trust Small Cap Core AlphaDEX® Fund	Nasdaq AlphaDEX Small Cap CoreTM Index
First Trust Small Cap Growth AlphaDEX® Fund	Nasdaq AlphaDEX Small Cap GrowthTM Index
First Trust Small Cap Value AlphaDEX® Fund	Nasdaq AlphaDEX Small Cap ValueTM Index

Types of Investments

Equities. Equity securities represent an ownership position in a company. The prices of equity securities fluctuate based on, among other things, events specific to their issuers and market, economic, and other conditions. Equity securities may include common and preferred stocks. Common stocks include the common stock of any class or series of a domestic or foreign corporation or any similar equity interest, such as a trust or partnership interest. These investments may or may not pay dividends and may or may not carry voting rights. Common stock occupies the most junior position in a company’s capital structure.

Fixed Income Investments and Cash Equivalents. Normally, the Funds invest substantially all of their assets to meet their investment objectives. However, for temporary or defensive purposes, the Funds may invest in fixed income investments and cash equivalents in order to provide income, liquidity and preserve capital.

Fixed income investments and cash equivalents held by each Fund may include, without limitation, the types of investments set forth below.

(1)

A Fund may invest in U.S. government securities, including bills, notes and bonds differing as to maturity and rates of interest, which are either issued or guaranteed by the U.S. Treasury or by U.S. government agencies or instrumentalities. U.S. government securities include securities that are issued or guaranteed by the U.S. Treasury, by various agencies of the U.S. government, or by various instrumentalities that have been established or sponsored by the U.S. government. U.S. Treasury securities are backed by the “full faith and credit” of the United States. Securities issued or guaranteed by federal agencies and U.S. government-sponsored instrumentalities may or may not be backed by the full faith and credit of the United

5

States. Some of the U.S. government agencies that issue or guarantee securities include the Export-Import Bank of the United States, the Farmers Home Administration, the Federal Housing Administration, the Maritime Administration, the Small Business Administration and The Tennessee Valley Authority. An instrumentality of the U.S. government is a government agency organized under federal charter with government supervision. Instrumentalities issuing or guaranteeing securities include, among others, the Federal Home Loan Banks, the Federal Land Banks, the Central Bank for Cooperatives, Federal Intermediate Credit Banks and the FNMA. In the case of those U.S. government securities not backed by the full faith and credit of the United States, the investor must look principally to the agency or instrumentality issuing or guaranteeing the security for ultimate repayment and may not be able to assert a claim against the United States itself in the event that the agency or instrumentality does not meet its commitment. The U.S. government, its agencies and instrumentalities do not guarantee the market value of their securities; consequently, the value of such securities may fluctuate. In addition, each Fund may invest in sovereign debt obligations of non-U.S. countries. A sovereign debtor’s willingness or ability to repay principal and interest in a timely manner may be affected by a number of factors, including its cash flow situation, the extent of its non-U.S. reserves, the availability of sufficient non-U.S. exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign debtor’s policy toward principal international lenders and the political constraints to which it may be subject.

(2)

A Fund may invest in certificates of deposit issued against funds deposited in a bank or savings and loan association. Such certificates are for a definite period of time, earn a specified rate of return and are normally negotiable. If such certificates of deposit are non-negotiable, they will be considered illiquid investments and be subject to a Fund's 15% restriction on investments in illiquid investments. Pursuant to the certificate of deposit, the issuer agrees to pay the amount deposited plus interest to the bearer of the certificate on the date specified thereon. Under current FDIC regulations, the maximum insurance payable as to any one certificate of deposit is $250,000; therefore, certificates of deposit purchased by a Fund may not be fully insured. A Fund may only invest in certificates of deposit issued by U.S. banks with at least $1 billion in assets.

(3)

A Fund may invest in bankers’ acceptances, which are short-term credit instruments used to finance commercial transactions. Generally, an acceptance is a time draft drawn on a bank by an exporter or an importer to obtain a stated amount of funds to pay for specific merchandise. The draft is then “accepted” by a bank that, in effect, unconditionally guarantees to pay the face value of the instrument on its maturity date. The acceptance may then be held by the accepting bank as an asset or it may be sold in the secondary market at the going rate of interest for a specific maturity.

(4)

A Fund may invest in repurchase agreements, which involve purchases of debt securities with counterparties that are deemed by First Trust to present acceptable credit risks. In such an action, at the time a Fund purchases the security, it simultaneously agrees to resell and redeliver the security to the seller, who also simultaneously agrees to buy back the security at a fixed price and time. This assures a predetermined yield for a Fund during its holding period since the resale price is always greater than the purchase price and reflects an agreed-upon market rate. Such actions afford an opportunity for a Fund to invest temporarily available cash. A Fund may enter into repurchase agreements only with respect to obligations of the U.S. government, its agencies or instrumentalities, certificates of deposit or bankers’ acceptances in which a Fund may invest. Repurchase agreements may be considered loans to the seller, collateralized by the underlying securities. The risk to a Fund is limited to the ability of the seller to pay the agreed-upon sum on the repurchase date; in the event of default, the repurchase agreement provides that the affected Fund is entitled to sell the underlying collateral. If the value of the collateral declines after the agreement is entered into, however, and if the seller defaults under a repurchase agreement when the value of the underlying collateral is less than the repurchase price, a Fund could incur a loss of both principal and interest. The portfolio managers monitor the value of the collateral at the time the action is entered into and at all times during the term of the repurchase agreement. The portfolio managers do so in an effort to determine that the value of the collateral always equals or exceeds the agreed-upon repurchase price to be paid to a Fund. If the seller were to be subject to a federal bankruptcy proceeding, the ability of a Fund to liquidate the collateral could be delayed or impaired because of certain provisions of the bankruptcy laws.

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(5)

A Fund may invest in bank time deposits, which are monies kept on deposit with banks or savings and loan associations for a stated period of time at a fixed rate of interest. There may be penalties for the early withdrawal of such time deposits, in which case the yields of these investments will be reduced.

(6)

A Fund may invest in commercial paper, which are short-term unsecured promissory notes, including variable rate master demand notes issued by corporations to finance their current operations. Master demand notes are direct lending arrangements between the Fund and a corporation. There is no secondary market for the notes. However, they are redeemable by a Fund at any time. The Investment Committee will consider the financial condition of the corporation (e.g., earning power, cash flow and other liquidity ratios) and will regularly monitor the corporation’s ability to meet all of its financial obligations, because a Fund's liquidity might be impaired if the corporation were unable to pay principal and interest on demand. A Fund may invest in commercial paper only if it has received the highest rating from at least one nationally recognized statistical rating organization or, if unrated, judged by First Trust to be of comparable quality.

(7)

A Fund may invest in shares of money market funds, as consistent with its investment objective and policies. Shares of money market funds are subject to management fees and other expenses of those funds. Therefore, investments in money market funds will cause the Fund to bear proportionately the costs incurred by the money market funds’ operations. At the same time, a Fund will continue to pay its own management fees and expenses with respect to all of its assets, including any portion invested in the shares of other investment companies. It is possible for the Fund to lose money by investing in money market funds.

Illiquid Investments. The Funds may invest in illiquid investments (i.e., any investment that a Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment).  For purposes of this restriction, illiquid investments may include, but are not limited to, certain restricted securities (securities the disposition of which is restricted under the federal securities laws), securities that may only be resold pursuant to Rule 144A under the 1933 Act, and repurchase agreements with maturities in excess of seven days, among others. However, a Fund will not acquire illiquid investments if, as a result, such investments would comprise more than 15% of the value of a Fund’s net assets. The Advisor, subject to oversight by the Board of Trustees, has the ultimate authority to determine, to the extent permissible under the federal securities laws, which investments are liquid or illiquid for purposes of this 15% limitation under a Fund’s liquidity risk management program, adopted pursuant to Rule 22e-4 under the 1940 Act.

Restricted securities may be sold only in privately negotiated transactions or in a public offering with respect to which a registration statement is in effect under the 1933 Act. Where registration is required, a Fund may be obligated to pay all or part of the registration expenses and a considerable period may elapse between the time of the decision to sell and the time a Fund may be permitted to sell a security under an effective registration statement. If, during such a period, adverse market conditions were to develop, a Fund might obtain a less favorable price than that which prevailed when it decided to sell. Illiquid investments will be priced at fair value as determined in good faith under procedures adopted by the Board of Trustees. If, through the appreciation of illiquid investments or the depreciation of liquid investments, a Fund should be in a position where more than 15% of the value of its net assets are invested in illiquid investments, including restricted securities which are not readily marketable, the Advisor will report such occurrence to the Board of Trustees and take such steps as are deemed advisable to protect liquidity in accordance with a Fund’s liquidity risk management program.

Real Estate Investment Trusts.  Real estate investment trusts (“REITs”)  are typically publicly traded corporations or trusts that invest in residential or commercial real estate. REITs generally can be divided into the following three types: (i) equity REITs which invest the majority of their assets directly in real property and derive their income primarily from rents and capital gains or real estate appreciation; (ii) mortgage REITs which invest the majority of their assets in real estate mortgage loans and derive their income primarily from interest payments; and (iii) hybrid REITs which combine the characteristics of equity REITs and mortgage REITs.

Portfolio Turnover

The Funds buy and sell portfolio securities in the normal course of their investment activities. The proportion of a Fund's investment portfolio that is bought and sold during a year is known as a Fund's portfolio turnover rate. A portfolio turnover rate of 100% would occur, for example, if all of the portfolio securities (other than short-term securities) were replaced once during the fiscal year. A high portfolio turnover rate could result in the payment by a Fund of increased brokerage costs, expenses and taxes. The portfolio turnover rates for the specified periods are set forth in the table below.

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Significant variations in portfolio turnover from year-to-year are generally the result of fluctuations in the size of a Fund or changes to a Fund’s portfolio holdings. 

Portfolio Turnover Rate
Fund	Fiscal Year Ended July 31,
	2024	2023
First Trust Consumer Discretionary AlphaDEX® Fund	84%	110%
First Trust Consumer Staples AlphaDEX® Fund	67%	63%
First Trust Energy AlphaDEX® Fund	60%	58%
First Trust Financials AlphaDEX® Fund	75%	78%
First Trust Health Care AlphaDEX® Fund	98%	94%
First Trust Industrials/Producer Durables AlphaDEX® Fund	78%	81%
First Trust Large Cap Core AlphaDEX® Fund	88%	87%
First Trust Large Cap Growth AlphaDEX® Fund	116%	127%
First Trust Large Cap Value AlphaDEX® Fund	81%	80%
First Trust Materials AlphaDEX® Fund	53%	35%
First Trust Mid Cap Core AlphaDEX® Fund	103%	106%
First Trust Mid Cap Growth AlphaDEX® Fund	134%	142%
First Trust Mid Cap Value AlphaDEX® Fund	98%	102%
First Trust Multi Cap Growth AlphaDEX® Fund	115%	125%
First Trust Multi Cap Value AlphaDEX® Fund	87%	85%
First Trust Small Cap Core AlphaDEX® Fund	112%	109%
First Trust Small Cap Growth AlphaDEX® Fund	141%	140%
First Trust Small Cap Value AlphaDEX® Fund	114%	110%
First Trust Technology AlphaDEX® Fund	119%	104%
First Trust Utilities AlphaDEX® Fund	53%	46%

Lending of Portfolio Securities

In order to generate additional income, as a non-principal investment strategy, First Trust is authorized to select certain First Trust Funds, including the Funds, with notice to the Board of Trustees, to lend portfolio securities representing up to 33⅓% of the value of their total assets to broker-dealers, banks or other institutional borrowers of securities. As with other extensions of credit, there may be risks of delay in recovery of the securities or even loss of rights in the collateral should the borrower of the securities fail financially. However, such First Trust Funds will only enter into loan arrangements with broker-dealers, banks or other institutions which First Trust has determined are creditworthy under guidelines approved by the Board of Trustees. The First Trust Funds will pay a portion of the income earned on the lending transaction to the placing broker and may pay administrative and custodial fees in connection with these loans. First Trust may select any First Trust Fund to participate in the securities lending program, at its discretion with notice to the Board of Trustees.

In these loan arrangements, the First Trust Funds will receive collateral in the form of cash, U.S. government securities or other high-grade debt obligations in an amount at least equal to the value of the borrowed securities, marked to market daily. This collateral must be valued daily by First Trust or the applicable First Trust Fund’s lending agent and, if the market value of the loaned securities increases, the borrower must furnish additional collateral to the lending First Trust Fund. During the time portfolio securities are on loan, the borrower pays the lending First Trust Fund any dividends or interest paid on the securities. Loans are subject to termination at any time by the lending First Trust Fund or the borrower. While a First Trust Fund does not have the right to vote securities on loan, it would terminate the loan and regain the right to vote if that were considered important with respect to the investment. When a First Trust Fund lends portfolio securities to a borrower, payments in lieu of dividends made by the borrower to the First Trust Fund will not constitute “qualified dividends” taxable at the same rate as long-term capital gains, even if the actual dividends would have constituted qualified dividends had the First Trust Fund held the securities. Please see "Securities Lending Risk" below for a description of the risks associated with securities lending activities.

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The following tables describe the securities lending activities of each Fund that engaged in securities lending activities during the fiscal year ended July 31, 2024: 

FIRST TRUST CONSUMER DISCRETIONARY ALPHADEX® FUND
Gross income from securities lending activities	$1,494,265
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	146,040
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	5,101
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	64,868
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	216,009
Net income from securities lending activities	$1,278,256
FIRST TRUST ENERGY ALPHADEX® FUND
Gross income from securities lending activities	$519,875
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	25,263
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	7,390
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	248,906
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	281,559
Net income from securities lending activities	$238,316
FIRST TRUST FINANCIALS ALPHADEX® FUND
Gross income from securities lending activities	$142,627
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	2,939
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	2,329
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	113,339
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	118,607
Net income from securities lending activities	$24,020

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FIRST TRUST HEALTH CARE ALPHADEX® FUND
Gross income from securities lending activities	$6,057
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	367
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	40
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	2,347
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	2,754
Net income from securities lending activities	$3,303
FIRST TRUST INDUSTRIALS/PRODUCER DURABLES ALPHADEX® FUND
Gross income from securities lending activities	$142,927
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	3,628
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	1,858
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	104,525
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	110,011
Net income from securities lending activities	$32,916
FIRST TRUST MATERIALS ALPHADEX® FUND
Gross income from securities lending activities	$9,340
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	781
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	47
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	0
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	828
Net income from securities lending activities	$8,512

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FIRST TRUST TECHNOLOGY ALPHADEX® FUND
Gross income from securities lending activities	$5,082,143
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	431,998
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	13,688
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	748,714
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	1,194,400
Net income from securities lending activities	$3,887,743
FIRST TRUST LARGE CAP CORE ALPHADEX® FUND
Gross income from securities lending activities	$48,531
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	1,495
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	633
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	32,788
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	34,916
Net income from securities lending activities	$13,615
FIRST TRUST LARGE CAP GROWTH ALPHADEX® FUND
Gross income from securities lending activities	$7,130
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	54
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	0
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	6,592
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	6,646
Net income from securities lending activities	$484

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FIRST TRUST LARGE CAP VALUE ALPHADEX® FUND
Gross income from securities lending activities	$82,332
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	1,740
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	1,166
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	63,769
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	66,675
Net income from securities lending activities	$15,657
FIRST TRUST MID CAP CORE ALPHADEX® FUND
Gross income from securities lending activities	$379,026
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	6,306
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	6,264
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	309,900
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	322,470
Net income from securities lending activities	$56,556
FIRST TRUST MID CAP GROWTH ALPHADEX® FUND
Gross income from securities lending activities	$123,323
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	2,275
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	1,931
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	94,383
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	98,589
Net income from securities lending activities	$24,734

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FIRST TRUST MID CAP VALUE ALPHADEX® FUND
Gross income from securities lending activities	$67,720
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	1,647
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	1,082
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	49,774
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	52,503
Net income from securities lending activities	$15,217
FIRST TRUST MULTI CAP GROWTH ALPHADEX® FUND
Gross income from securities lending activities	$74,826
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	4,055
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	676
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	22,229
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	26,960
Net income from securities lending activities	$47,866
FIRST TRUST MULTI CAP VALUE ALPHADEX® FUND
Gross income from securities lending activities	$30,923
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	946
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	467
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	20,321
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	21,734
Net income from securities lending activities	$9,189

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FIRST TRUST SMALL CAP CORE ALPHADEX® FUND
Gross income from securities lending activities	$807,499
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	44,795
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	6,749
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	207,903
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	259,447
Net income from securities lending activities	$548,052
FIRST TRUST SMALL CAP GROWTH ALPHADEX® FUND
Gross income from securities lending activities	$265,339
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	36,926
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	0
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	(103,248)
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	(66,322)
Net income from securities lending activities	$331,661
FIRST TRUST SMALL CAP VALUE ALPHADEX® FUND
Gross income from securities lending activities	$57,242
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	2,678
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	818
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	24,141
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	27,637
Net income from securities lending activities	$29,605

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FIRST TRUST UTILITIES ALPHADEX® FUND
Gross income from securities lending activities	$94,436
Fees and/or compensation for securities lending activities and related services
Fees paid to securities lending agent from a revenue split	2,905
Fees paid for any cash collateral management service (including fees deducted from a  pooled cash collateral reinvestment vehicle) that are not included in the revenue split	1,498
Administrative fees not included in revenue split	0
Indemnification fee not included in revenue split	0
Rebate (paid to borrower)	63,882
Other fees not included in revenue split (specify)	0
Aggregate fees/compensation for securities lending activities	68,285
Net income from securities lending activities	$26,151

The Bank of New York Mellon Corporation (the “Securities Lending Agent”) may serve as securities lending agent for the Funds. The services provided by the Securities Lending Agent include: the coordination and selection of securities to be loaned to approved borrowers; negotiating the terms of the loan; monitoring the value of securities loaned and corresponding collateral, marking to market daily; coordinating the investment of cash collateral in the Funds’ approved cash collateral reinvestment vehicle; monitoring dividends and coordinating material proxy votes relating to loaned securities; and transferring, recalling and arranging the return of loaned securities to the Funds upon termination of the loan.

Sublicense Agreements

The Trust, on behalf of each Fund, has entered into a sublicense agreement (each a “Sublicense Agreement”) with First Trust, FTP and each Fund’s corresponding Index Provider that grants each Fund and First Trust an exclusive and transferable sublicense to use certain intellectual property of such Index Provider in connection with the issuance, distribution, marketing and/or promotion of the applicable Fund. Pursuant to each Sublicense Agreement, the Trust, on behalf of each Fund, and First Trust have agreed to be bound by certain provisions of the product license agreement by and between the corresponding Index Provider and FTP (each a “Product License Agreement”).

Investment Risks

The following risk disclosure supplements the discussion of the Funds' investment risks that appears in the Prospectus.

Overview

An investment in a Fund should be made with an understanding of the risks that an investment in the Fund's shares entails, including the risk that the financial condition of the issuers of the equity securities held by a Fund or the general condition of the securities market may worsen and the value of the equity securities and therefore the value of a Fund may decline. A Fund may not be an appropriate investment for those who are unable or unwilling to assume the risks involved generally with such an investment. The past market and earnings performance of any of the equity securities included in a Fund is not predictive of their future performance.

Additional Market Disruption Risk

In February 2022, Russia commenced a military attack on Ukraine. In response, various countries, including the United States, issued broad-ranging sanctions on Russia and certain Russian companies and individuals. The hostilities between the two countries may escalate and any existing or future sanctions could have a severe adverse effect on Russia’s economy, currency, companies and region as well as negatively impact other regional and global economic markets of the world (including Europe and the United States), companies in such countries and various sectors, industries and markets for securities and commodities globally, such as oil and natural gas. Accordingly, the hostilities and sanctions may have a negative effect on a Fund's investments and performance beyond any direct exposure to Russian issuers or those of adjoining geographic regions. Russia may also take retaliatory actions or countermeasures, such as cyberattacks and espionage, which may negatively impact the countries and companies in which a Fund may invest. The extent and duration of the military action or future escalation of such hostilities; the extent and impact of existing and any future sanctions,

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market disruptions and volatility; and the result of any diplomatic negotiations cannot be predicted. These and any related events could have a significant negative impact on certain of a Fund’s investments as well as a Fund’s performance, and the value or liquidity of certain securities held by a Fund may decline significantly.

Common Stock Risk

Equity securities are especially susceptible to general market movements and to volatile increases and decreases of value as market confidence in and perceptions of the issuers change. These perceptions are based on unpredictable factors including expectations regarding government, economic, monetary and fiscal policies, inflation and interest rates, economic expansion or contraction, and global or regional political, economic or banking crises. First Trust cannot predict the direction or scope of any of these factors. Shareholders of common stocks have rights to receive payments from the issuers of those common stocks that are generally subordinate to those of creditors of, or holders of debt obligations or preferred stocks of, such issuers.

Shareholders of common stocks of the type held by the Funds have a right to receive dividends only when and if, and in the amounts, declared by the issuer’s board of directors and have a right to participate in amounts available for distribution by the issuer only after all other claims on the issuer have been paid or otherwise been settled. Common stocks do not represent an obligation of the issuer and, therefore, do not offer any assurance of income or provide the same degree of protection of capital as do debt securities. The issuance of additional debt securities or preferred stock will create prior claims for payment of principal, interest and dividends which could adversely affect the ability and inclination of the issuer to declare or pay dividends on its common stock or the rights of holders of common stock with respect to assets of the issuer upon liquidation or bankruptcy. The value of common stocks is subject to market fluctuations for as long as the common stocks remain outstanding, and thus the value of the equity securities in the Funds will fluctuate over the life of the Funds and may be more or less than the price at which they were purchased by the Funds. The equity securities held in the Funds may appreciate or depreciate in value (or pay dividends) depending on the full range of economic and market influences affecting these securities, including the impact of a Fund’s purchase and sale of the equity securities and other factors.

Holders of common stocks incur more risk than holders of preferred stocks and debt obligations because common stockholders, as owners of the entity, have generally inferior rights to receive payments from the issuer in comparison with the rights of creditors of, or holders of debt obligations or preferred stocks issued by the issuer. Cumulative preferred stock dividends must be paid before common stock dividends and any cumulative preferred stock dividend omitted is added to future dividends payable to the holders of cumulative preferred stock. Preferred stockholders are also generally entitled to rights on liquidation which are senior to those of common stockholders.

Dividends Risk

Shareholders of common stocks have rights to receive payments from the issuers of those common stocks that are generally subordinate to those of creditors of, or holders of debt obligations or preferred stocks of, such issuers. Shareholders of common stocks of the type held by the Funds have a right to receive dividends only when and if, and in the amounts, declared by the issuer’s board of directors and have a right to participate in amounts available for distribution by the issuer only after all other claims on the issuer have been paid or have otherwise been settled. Common stocks do not represent an obligation of the issuer and, therefore, do not offer any assurance of income or provide the same degree of protection of capital as do debt securities. The issuance of additional debt securities or preferred stock will create prior claims for payment of principal, interest and dividends which could adversely affect the ability and inclination of the issuer to declare or pay dividends on its common stock or the rights of holders of common stock with respect to assets of the issuer upon liquidation or bankruptcy. Cumulative preferred stock dividends must be paid before common stock dividends, and any cumulative preferred stock dividend omitted is added to future dividends payable to the holders of cumulative preferred stock. Preferred stockholders are also generally entitled to rights on liquidation that are senior to those of common stockholders.

Liquidity Risk

Whether or not the equity securities held by the Funds are listed on a securities exchange, the principal trading market for certain of the equity securities in a Fund may be in the over-the-counter (“OTC”) market. As a result, the existence of a liquid trading market for the equity securities may depend on whether dealers will make a market in the equity securities. Certain regions, countries or asset types may also suffer periods of relative illiquidity.  There can be no assurance that a market will be made for any of the equity securities, that any market for the equity securities will be maintained or that there will be sufficient liquidity of the equity securities in any markets made. The price at which the equity securities are held by the Funds will be adversely affected if trading markets for the equity securities are limited or absent.

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Listing Standards Risk

Each Fund is required to comply with listing requirements adopted by the Exchange. Non-compliance with such requirements may result in a Fund's shares being delisted by the Exchange. Any resulting liquidation of a Fund could cause the Fund to incur elevated transaction costs and could result in negative tax consequences for its shareholders.

Litigation Risk

At any time litigation may be instituted on a variety of grounds with respect to the common stocks held by the Funds. The Funds are unable to predict whether litigation that has been or will be instituted might have a material adverse effect on the Funds.

Market Risk

Market risk is the risk that a particular security, or shares of a Fund in general, may fall in value. Securities are subject to market fluctuations caused by such factors as economic, political, regulatory or market developments, changes in interest rates and perceived trends in securities prices. Shares of a Fund could decline in value or underperform other investments due to short-term market movements or any longer periods during more prolonged market downturns. In addition, local, regional or global events such as war, acts of terrorism, spread of infectious diseases or other public health issues, recessions, natural disasters or other events could have a significant negative impact on a Fund and its investments. Such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Such events could adversely affect the prices and liquidity of a Fund’s portfolio securities or other instruments and could result in disruptions in the trading markets. Any of such circumstances could have a materially negative impact on the value of a Fund’s shares and result in increased market volatility. During any such events, a Fund’s shares may trade at increased premiums or discounts to their net asset value and the bid/ask spread on a Fund’s shares may widen.

Health crises caused by the outbreak of infectious diseases or other public health issues, may exacerbate other pre-existing political, social, economic, market and financial risks. The impact of any such events, could negatively affect the global economy, as well as the economies of individual countries or regions, the financial performance of individual companies, sectors and industries, and the markets in general in significant and unforeseen ways. Any such impact could adversely affect the prices and liquidity of the securities and other instruments in which a Fund invests and negatively impact a Fund’s investment return. For example, an outbreak of a respiratory disease designated as COVID-19 was first detected in China in December 2019 and subsequently spread internationally. The ensuing policies enacted by governments and central banks have caused and may continue to cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. While vaccines have been developed, there is no guarantee that vaccines will be effective against future variants of the disease. The impact of the COVID-19 pandemic may be short term or may last for an extended period of time, and in either case could result in a substantial economic downturn or recession.

In addition, the operations of a Fund, the Advisor and a Fund’s other service providers may be significantly impacted, or even temporarily or permanently halted, as a result of government quarantine measures, voluntary and precautionary restrictions on travel or meetings and other factors related to a public health emergency, including its potential adverse impact on the health of any such entity’s personnel.

Real Estate Investment Trust Risk

REITs are financial vehicles that pool investors’ capital to purchase or finance real estate. REITs may concentrate their investments in specific geographic areas or in specific property types, e.g., hotels, shopping malls, residential complexes and office buildings. The market value of REIT shares and the ability of the REITs to distribute income may be adversely affected by several factors, including rising interest rates; changes in the national, state and local economic climate and real estate conditions; perceptions of prospective tenants of the safety, convenience and attractiveness of the properties; the ability of the owners to provide adequate management, maintenance and insurance; the cost of complying with the Americans with Disabilities Act; increased competition from new properties; the impact of present or future environmental legislation and compliance with environmental laws; changes in real estate taxes and other operating expenses; adverse changes in governmental rules and fiscal policies; adverse changes in zoning laws; and other factors beyond the control of the issuers of the REITs. In addition, distributions received by the Fund from REITs may consist of dividends, capital gains and/or return of capital. Many of these distributions however will not generally qualify for favorable treatment as qualified dividend income.

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Securities Lending Risk

Securities lending involves exposure to certain risks, including counterparty risk, collateral risk and operational risk. Counterparty risk is the risk that the borrower may fail to return the securities in a timely manner or at all. As a result, a First Trust Fund engaged in securities lending transactions may suffer a loss and there may be a delay in recovering the lent securities. Any delay in the return of securities on loan may restrict the ability of a Fund to meet delivery or payment obligations. Collateral risk is the risk that the collateral received may be realized at a value lower than the value of the securities lent, whether due to inaccurate pricing of the collateral, adverse market movements in the value of the collateral, intra-day increases in the value of the securities lent, a deterioration in the credit rating of the collateral issuer, or the illiquidity of the market in which the collateral is traded. Securities lending also entails operational risks, such as settlement failures or delays in the settlement of instructions. Such failures or delays may restrict the ability of a Fund to meet delivery or payment obligations. Lastly, securities lending activities may result in adverse tax consequences for a Fund and its shareholders. For instance, substitute payments for dividends received by a Fund for securities loaned out by the Fund will not be considered qualified dividend income. A Fund could lose money if its short-term investment of the collateral declines in value over the period of the loan.

Small and Mid Capitalization Companies Risk

Certain of the equity securities in certain Funds may be small and/or mid capitalization company stocks. While historically such company stocks have outperformed the stocks of large companies, the former have customarily involved more investment risk as well. Small and mid capitalization companies may have limited product lines, markets or financial resources; may lack management depth or experience; and may be more vulnerable to adverse general market or economic developments than large companies. Some of these companies may distribute, sell or produce products which have recently been brought to market and may be dependent on key personnel.

The prices of small and mid capitalization company securities are often more volatile than prices associated with large company issues, and can display abrupt or erratic movements at times, due to limited trading volumes and less publicly available information. Also, because small and mid capitalization companies normally have fewer shares outstanding and these shares trade less frequently than large companies, it may be more difficult for a Fund which contains these equity securities to buy and sell significant amounts of such shares without an unfavorable impact on prevailing market prices. The securities of small and mid capitalization companies are often traded OTC and may not be traded in the volumes typical of a national securities exchange.

Variable Interest Entities Risk

In order to gain exposure to certain Chinese companies that are included in a Fund’s Index but are unavailable to direct investment by foreign investors, certain Funds invest significantly in non-Chinese shell companies that have created structures known as variable interest entities (“VIEs”) in order to gain exposure to such Chinese companies. In China, direct ownership of companies in certain sectors by foreign individuals and entities is prohibited. In order to allow for foreign investment in these businesses, many Chinese companies have created VIE structures to enable indirect foreign ownership. In such an arrangement, a Chinese operating company typically establishes an offshore shell company in another jurisdiction, such as the Cayman Islands. That shell company enters into service and other contracts with the Chinese issuer or operating company to obtain economic exposure to the Chinese company, then issues shares on an exchange outside of mainland China, and U.S. investors hold stock in the non-Chinese shell company rather than directly in the Chinese issuer or operating company. This arrangement allows U.S. investors, such as the Fund, to obtain economic exposure to the Chinese issuer or operating company through contractual means rather than through formal equity ownership. Because neither the shell company nor the Fund owns actual equity interests in the Chinese operating company, they do not have the voting rights or other types of control that an equity holder would expect to benefit from. Although VIEs are a longstanding industry practice and well known to officials and regulators in China, VIEs are not formally recognized under Chinese law. Intervention by the Chinese government with respect to VIEs could significantly affect the Chinese company’s performance and the enforceability of the VIE’s contractual arrangements that establish the links between the Chinese company and the shell company in which the Fund invests. This could considerably impact the financial condition of the shell company in which the Fund invests by limiting its ability to consolidate the financial results of the Chinese operating company into its own financial statements, as well as make the value of the shares held by the Fund effectively worthless. Further, if Chinese officials prohibit the existence of VIEs, the market value of the Fund’s associated holdings would likely suffer significant, and possibly permanent effects, which could negatively impact the Fund’s net asset value and could result in substantial losses. Further, it is uncertain whether any new laws, rules or regulations relating to VIE structures will be adopted or, if adopted, what impact they would have on the value of the Fund’s shares.

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VIEs are also subject to the investment risks associated with the underlying Chinese issuer or operating company. Chinese companies are not subject to the same degree of regulatory requirements or accounting standards and oversight as companies in more developed countries. As a result, information about the Chinese securities and VIEs in which the Fund invests may be less reliable and incomplete. There also may be significant obstacles to obtaining information necessary for investigations into or litigation against Chinese companies and VIEs, and shareholders may have limited legal remedies, which could negatively impact the Fund. Additionally, U.S.-listed VIEs may be delisted if they do not meet U.S. accounting standards and auditor oversight requirements. Delisting would significantly decrease the liquidity and value of the securities, decrease the ability of the Fund to invest in such securities and may increase the cost of the Fund if required to seek alternative markets in which to invest in such securities.

Management of the Funds

Trustees and Officers

The general supervision of the duties performed for the Funds under the investment management agreement is the responsibility of the Board of Trustees. There are seven Trustees of the Trust, one of whom is an “interested person” (as the term is defined in the 1940 Act) and six of whom are Trustees who are not officers or employees of First Trust or any of its affiliates (“Independent Trustees”). The Trustees set broad policies for the Funds, choose the Trust’s officers and hire the Trust’s investment advisor. The officers of the Trust manage its day-to-day operations and are responsible to the Board of Trustees. The following is a list of the Trustees and executive officers of the Trust and a statement of their present positions and principal occupations during the past five years, the number of portfolios each Trustee oversees and the other directorships they have held during the past five years, if applicable. Each Trustee has been elected for an indefinite term. The officers of the Trust serve indefinite terms. Each Trustee, except for James A. Bowen, is an Independent Trustee. Mr. Bowen is deemed an “interested person” (as that term is defined in the 1940 Act) (“Interested Trustee”) of the Trust due to his position as Chief Executive Officer of First Trust, investment advisor to the Funds. The following table identifies the Trustees and Officers of the Trust. Unless otherwise indicated, the address of all persons below is c/o First Trust Advisors L.P., 120 East Liberty Drive, Suite 400, Wheaton, IL 60187. 

Name and Year of Birth	Position and Offices with Trust	Term of Office and Year First Elected or Appointed	Principal Occupations During Past 5 Years	Number of Portfolios in the First Trust Fund Complex Overseen by Trustee	Other Trusteeships or Directorships Held by Trustee During the Past 5 Years
TRUSTEE WHO IS AN INTERESTED PERSON OF THE TRUST
James A. Bowen (1) 1955	Chairman of the Board and Trustee	●Indefinite term ●Since inception	Chief Executive Officer, First Trust Advisors L.P. and First Trust Portfolios L.P.; Chairman of the Board of Directors, BondWave LLC (Software Development Company) and Stonebridge Advisors LLC (Investment Advisor)	299 Portfolios	None
INDEPENDENT TRUSTEES
Richard E. Erickson 1951	Trustee	●Indefinite term ●Since inception	Retired; Physician, Edward-Elmhurst Medical Group (2021 to September 2023); Physician and Officer, Wheaton Orthopedics (1990 to 2021)	299 Portfolios	None
Thomas R. Kadlec 1957	Trustee	●Indefinite term ●Since inception	Retired; President, ADM Investor Services, Inc. (Futures Commission Merchant) (2010 to July 2022)	299 Portfolios	Director, National Futures Association; formerly, Director of ADM Investor Services, Inc., ADM Investor Services International, ADMIS Hong Kong Ltd., ADMIS Singapore Ltd. and Futures Industry Association

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Name and Year of Birth	Position and Offices with Trust	Term of Office and Year First Elected or Appointed	Principal Occupations During Past 5 Years	Number of Portfolios in the First Trust Fund Complex Overseen by Trustee	Other Trusteeships or Directorships Held by Trustee During the Past 5 Years
INDEPENDENT TRUSTEES
Denise M. Keefe 1964	Trustee	●Indefinite term ●Since 2021	Senior Vice President, Advocate Health, Continuing Health Division (Integrated Healthcare System) (2023 to present); Executive Vice President, Advocate Aurora Health (Integrated Healthcare System) (2018 to 2023)	299 Portfolios	Director and Board Chair of Advocate Home Health Services, Advocate Home Care Products and Advocate Hospice; Director and Board Chair of Aurora At Home (since 2018); Director of Advocate Physician Partners Accountable Care Organization; Director of RML Long Term Acute Care Hospitals; Director of Senior Helpers (2021 to 2024); and Director of MobileHelp (2022 to 2024)
Robert F. Keith 1956	Trustee	●Indefinite term ●Since inception	President, Hibs Enterprises (Financial and Management Consulting)	299 Portfolios	Formerly, Director of Trust Company of Illinois
Niel B. Nielson 1954	Trustee	●Indefinite term ●Since inception	Senior Advisor (2018 to present), Managing Director and Chief Operating Officer (2015 to 2018), Pelita Harapan Educational Foundation (Educational Products and Services)	299 Portfolios	None
Bronwyn Wright 1971	Trustee	●Indefinite term ●Since 2023	Independent Director to a number of Irish collective investment funds (2009 to present); Various roles at international affiliates of Citibank (1994 to 2009), including Managing Director, Citibank Europe plc and Head of Securities and Fund Services, Citi Ireland (2007 to 2009)	273 Portfolios	None

 

Name and Year of Birth	Position and Offices with Trust	Term of Office and Length of Service	Principal Occupations During Past 5 Years
OFFICERS OF THE TRUST
James M. Dykas 1966	President and Chief Executive Officer	●Indefinite term ●Since 2016	Managing Director and Chief Financial Officer, First Trust Advisors L.P. and First Trust Portfolios L.P.; Chief Financial Officer, BondWave LLC (Software Development Company) and Stonebridge Advisors LLC (Investment Advisor)
W. Scott Jardine 1960	Secretary and Chief Legal Officer	●Indefinite term ●Since inception	General Counsel, First Trust Advisors L.P. and First Trust Portfolios L.P.; Secretary and General Counsel, BondWave LLC; and Secretary, Stonebridge Advisors LLC
Daniel J. Lindquist 1970	Vice President	●Indefinite term ●Since inception	Managing Director, First Trust Advisors L.P. and First Trust Portfolios L.P.
Kristi A. Maher 1966	Chief Compliance Officer and Assistant Secretary	●Indefinite term ●Chief Compliance Officer since January 2011 ●Assistant Secretary since inception	Deputy General Counsel, First Trust Advisors L.P. and First Trust Portfolios L.P.

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Name and Year of Birth	Position and Offices with Trust	Term of Office and Length of Service	Principal Occupations During Past 5 Years
Derek D. Maltbie 1972	Treasurer, Chief Financial Officer and Chief Accounting Officer	●Indefinite term ●Since 2023	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P., July 2021 – present. Previously, Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P., 2014 –2021.
Roger F. Testin 1966	Vice President	●Indefinite term ●Since inception	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.
Stan Ueland 1970	Vice President	●Indefinite term ●Since inception	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.

(1)

Mr. Bowen is deemed an “interested person” of the Trust due to his position as Chief Executive Officer of First Trust, investment advisor of the Funds.

Unitary Board Leadership Structure

Except in certain circumstances (as noted below) under which a Trustee is unable to sit on all the boards of all the funds in the First Trust Fund Complex (as defined below), each Trustee serves as a trustee of all open-end and closed-end funds in the First Trust Fund Complex (as defined below), which is known as a “unitary” board leadership structure. Each Trustee (except as noted below) currently serves as a trustee of First Trust Series Fund and First Trust Variable Insurance Trust, open-end funds with 12 portfolios advised by First Trust; First Trust Senior Floating Rate Income Fund II, First Trust Enhanced Equity Income Fund, First Trust Mortgage Income Fund, First Trust Specialty Finance and Financial Opportunities Fund, First Trust Intermediate Duration Preferred & Income Fund and First Trust High Yield Opportunities 2027 Term Fund, closed-end funds advised by First Trust; and First Trust Exchange-Traded Fund, First Trust Exchange-Traded Fund II, First Trust Exchange-Traded Fund III, First Trust Exchange-Traded Fund IV, First Trust Exchange-Traded Fund V, First Trust Exchange-Traded Fund VI, First Trust Exchange-Traded Fund VII, First Trust Exchange-Traded Fund VIII, First Trust Exchange-Traded AlphaDEX® Fund and First Trust Exchange-Traded AlphaDEX® Fund II, exchange-traded funds with 281 portfolios advised by First Trust (each a “First Trust Fund” and collectively, the “First Trust Fund Complex”). Ms. Wright also serves as director of First Trust Global Funds, a public limited company established in Ireland and an open-end umbrella fund representing 34 exchange-traded funds and one mutual fund, and advised by First Trust (collectively, the “First Trust UCITS”). In addition, Ms. Wright had previously served on the board of directors of First Trust Global Portfolios Management Limited, the manager to the First Trust UCITS and an affiliate of First Trust, but resigned such position effective March 6, 2023. Except as noted above, none of the Independent Trustees nor their immediate family members has ever been a director, officer or employee of, or consultant to, First Trust, First Trust Portfolios L.P. or their affiliates. Due to certain restrictions resulting from the 1940 Act, Ms. Wright does not serve as a Trustee of First Trust Exchange-Traded Fund, with, in the aggregate, 26 portfolios.

The management of the Funds, including general supervision of the duties performed for the Funds under the investment management agreement between the Trust, on behalf of the Funds, and the Advisor, is the responsibility of the Board of Trustees. The Trustees of the Trust set broad policies for the Funds, choose the Trust’s officers and hire the Funds' investment advisor and other service providers. The officers of the Trust manage the day-to-day operations and are responsible to the Trust’s Board. The Trust’s Board is composed of six Independent Trustees and one Interested Trustee. The Interested Trustee, James A. Bowen, serves as the Chairman of the Board for each fund in the First Trust Fund Complex.

The unitary board structure was adopted for the First Trust Funds because of the efficiencies it achieves with respect to the governance and oversight of the First Trust Funds. Each First Trust Fund is subject to the rules and regulations of the 1940 Act (and other applicable securities laws), which means that many of the First Trust Funds face similar issues with respect to certain of their fundamental activities, including risk management, portfolio liquidity, portfolio valuation and financial reporting. Because of the similar and often overlapping issues facing the First Trust Funds, including among the First Trust exchange-traded funds, the Board of the First Trust Funds believes that maintaining a unitary board structure promotes efficiency and consistency in the governance and oversight of all First Trust Funds and reduces the costs, administrative burdens and possible conflicts that may result from having multiple boards. In adopting a unitary board structure, the Trustees seek to provide effective governance through establishing a board the overall composition of which will, as a body, possess the appropriate skills, diversity, independence and experience to oversee the Funds' business.

Annually, the Board reviews its governance structure and the committee structures, their performance and functions, and it reviews any processes that would enhance Board governance over the Funds' business. The Board has determined that its leadership structure, including the unitary board and committee structure, is appropriate based on the characteristics of the funds it serves and the characteristics of the First Trust Fund Complex as a whole.

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In order to streamline communication between the Advisor and the Independent Trustees and create certain efficiencies, the Board has a Lead Independent Trustee who is responsible for: (i) coordinating activities of the Independent Trustees; (ii) working with the Advisor, Fund counsel and the independent legal counsel to the Independent Trustees to determine the agenda for Board meetings; (iii) serving as the principal contact for and facilitating communication between the Independent Trustees and the Funds' service providers, particularly the Advisor; and (iv) any other duties that the Independent Trustees may delegate to the Lead Independent Trustee. The Lead Independent Trustee is selected by the Independent Trustees and serves a three-year term or until his or her successor is selected.

The Board has established five standing committees (as described below) and has delegated certain of its responsibilities to those committees. The Board and its committees meet frequently throughout the year to oversee the Funds' activities, review contractual arrangements with and performance of service providers, oversee compliance with regulatory requirements and review Fund performance. The Independent Trustees are represented by independent legal counsel at all Board and committee meetings (other than meetings of the Dividend Committee). Generally, the Board acts by majority vote of all the Trustees, including a majority vote of the Independent Trustees if required by applicable law.

The four Committee Chairs and the Lead Independent Trustee rotate every three years in serving as Chair of the Audit Committee, the Nominating and Governance Committee, the Valuation Committee or the Dividend Committee, or as Lead Independent Trustee. The Lead Independent Trustee and immediate past Lead Independent Trustee also serve on the Executive Committee with the Interested Trustee.

The five standing committees of the First Trust Fund Complex are: the Executive Committee, the Nominating and Governance Committee, the Valuation Committee, the Audit Committee and the Dividend Committee. The Executive Committee, which meets between Board meetings, is authorized to exercise all powers of and to act in the place of the Board of Trustees to the extent permitted by the Trust’s Declaration of Trust and By Laws. Mr. Nielson, Mr. Bowen and Dr. Erickson are members of the Executive Committee. During the last fiscal year, the Executive Committee did not hold any meetings.

The Nominating and Governance Committee is responsible for appointing and nominating non-interested persons to the Trust’s Board of Trustees. Messrs. Erickson, Kadlec, Keith, Nielson and Mses. Keefe and Wright are members of the Nominating and Governance Committee. If there is no vacancy on the Board of Trustees, the Board will not actively seek recommendations from other parties, including shareholders. The Board of Trustees adopted a mandatory retirement age of 75 for Trustees, beyond which age Trustees are ineligible to serve. The Committee will not consider new trustee candidates who are 72 years of age or older. When a vacancy on the Board of Trustees occurs and nominations are sought to fill such vacancy, the Nominating and Governance Committee may seek nominations from those sources it deems appropriate in its discretion, including shareholders of the applicable Funds. To submit a recommendation for nomination as a candidate for a position on the Board of Trustees, shareholders of the applicable Funds should mail such recommendation to W. Scott Jardine, Secretary, at the Trust’s address, 120 East Liberty Drive, Suite 400, Wheaton, Illinois 60187. Such recommendation shall include the following information: (i) evidence of Fund ownership of the person or entity recommending the candidate (if a Fund shareholder); (ii) a full description of the proposed candidate’s background, including education, experience, current employment and date of birth; (iii) names and addresses of at least three professional references for the candidate; (iv) information as to whether the candidate is an “interested person” in relation to the Funds, as such term is defined in the 1940 Act, and such other information that may be considered to impair the candidate’s independence; and (v) any other information that may be helpful to the Committee in evaluating the candidate. If a recommendation is received with satisfactorily completed information regarding a candidate during a time when a vacancy exists on the Board or during such other time as the Nominating and Governance Committee is accepting recommendations, the recommendation will be forwarded to the Chair of the Nominating and Governance Committee and to counsel to the Independent Trustees. Recommendations received at any other time will be kept on file until such time as the Nominating and Governance Committee is accepting recommendations, at which point they may be considered for nomination. During the last fiscal year, the Nominating and Governance Committee held four meetings.

The Valuation Committee is responsible for the oversight of the Advisor as the “Valuation Designee” under Rule 2a-5 of the 1940 Act and its implementation of the valuation of the securities held in the Funds’ portfolios. Messrs. Erickson, Kadlec, Keith, Nielson and Mses. Keefe and Wright are members of the Valuation Committee. During the last fiscal year, the Valuation Committee held four meetings.

The Audit Committee is responsible for overseeing each Fund’s accounting and financial reporting process, the system of internal controls and audit process and for evaluating and appointing independent auditors (subject also to Board approval). Messrs. Erickson, Kadlec, Keith, Nielson and Mses. Keefe and Wright serve on the Audit Committee. Ms. Keefe was

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appointed to serve as the Vice Chair of the Audit Committee, effective March 12, 2024. During the last fiscal year, the Audit Committee held eight meetings.

The Dividend Committee is responsible for assisting the Board in, or assuming the authority and power of the Board with respect to, the declaration and setting of each Fund's dividends. Messrs. Keith and Nielson serve on the Dividend Committee. During the last fiscal year, the Dividend Committee did not hold any meetings.

Executive Officers

The executive officers of the Trust hold the same positions with each fund in the First Trust Fund Complex (representing 299 portfolios) as they hold with the Trust.

Risk Oversight

As part of the general oversight of the Funds, the Board is involved in the risk oversight of the Funds. The Board has adopted and periodically reviews policies and procedures designed to address each Fund’s risks. Oversight of investment and compliance risk is performed primarily at the Board level in conjunction with the Advisor’s investment oversight group and the Trust’s Chief Compliance Officer (“CCO”). Oversight of other risks also occurs at the committee level. The Advisor’s investment oversight group reports to the Board at quarterly meetings regarding, among other things, Fund performance and the various drivers of such performance. The Board reviews reports on the Funds' and the service providers’ compliance policies and procedures at each quarterly Board meeting and receives an annual report from the CCO regarding the operations of the Funds' and the service providers’ compliance programs. In addition, the Independent Trustees meet privately each quarter with the CCO. The Audit Committee reviews, with the Advisor and the Funds' independent auditors, each Fund’s major financial risk exposures and the steps the Advisor has taken to monitor and control these exposures, including each Fund’s risk assessment and risk management policies and guidelines. The Audit Committee also, as appropriate, reviews in a general manner the processes other Board committees have in place with respect to risk assessment and risk management. The Nominating and Governance Committee monitors all matters related to the corporate governance of the Trust. The Valuation Committee monitors valuation risk and oversees the Advisor's performance as Valuation Designee.

Not all risks that may affect the Funds can be identified nor can controls be developed to eliminate or mitigate their occurrence or effects. It may not be practical or cost effective to eliminate or mitigate certain risks, the processes and controls employed to address certain risks may be limited in their effectiveness, and some risks are simply beyond the reasonable control of the Funds or the Advisor or other service providers. For instance, as the use of Internet technology has become more prevalent, the Funds and their service providers have become more susceptible to potential operational risks through breaches in cyber security (generally, intentional and unintentional events that may cause a Fund or a service provider to lose proprietary information, suffer data corruption or lose operational capacity). There can be no guarantee that any risk management systems established by the Funds, their service providers, or issuers of the securities in which the Funds invest to reduce cyber security risks will succeed, and the Funds cannot control such systems put in place by service providers, issuers or other third parties whose operations may affect the Funds and/or their shareholders. Moreover, it is necessary to bear certain risks (such as investment-related risks) to achieve a Fund's goals. As a result of the foregoing and other factors, a Fund's ability to manage risk is subject to substantial limitations.

Board Diversification and Trustee Qualifications

As described above, the Nominating and Governance Committee of the Board oversees matters related to the selection and nomination of Trustees. The Nominating and Governance Committee seeks to establish an effective Board with an appropriate range of skills and diversity, including, as appropriate, differences in background, professional experience, education, vocation, and other individual characteristics and traits in the aggregate. Each Trustee must meet certain basic requirements, including relevant skills and experience, time availability and, if qualifying as an Independent Trustee, independence from the Advisor, underwriters or other service providers, including any affiliates of these entities.

Listed below for each current Trustee are the experiences, qualifications and attributes that led to the conclusion, as of the date of this SAI, that each current Trustee should serve as a Trustee in light of the Trust’s business and structure.

Richard E. Erickson, M.D., was previously an orthopedic surgeon with Edward-Elmhurst Medical Group from 2021 to September 2023. Prior thereto, he was President of Wheaton Orthopedics (from 1990 to 2021), a co-owner and director of a fitness center and a limited partner of two real estate companies. Dr. Erickson has served as a Trustee of each First Trust

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Fund since its inception and of the First Trust Funds since 1999. Dr. Erickson has also served as the Lead Independent Trustee (2008–2009 and 2017–2019) and on the Executive Committee (2008–2009 and 2017–2022), Chairman of the Nominating and Governance Committee (2003–2007 and 2014–2016), Chairman of the Audit Committee (2012–2013) and Chairman of the Valuation Committee (June 2006–2007; 2010–2011 and 2020–2022) of the First Trust Funds. He currently serves as Chairman of the Audit Committee (since January 1, 2023) of the First Trust Funds.

Thomas R. Kadlec was previously President of ADM Investor Services Inc. (“ADMIS”), a futures commission merchant and wholly-owned subsidiary of the Archer Daniels Midland Company (“ADM”) from 2010 to July 2022. Mr. Kadlec was employed by ADMIS and its affiliates since 1990 in various accounting, financial, operations and risk management capacities. Mr. Kadlec served on the boards of several international affiliates of ADMIS until July 2022 and served as a member of ADM’s Integrated Risk Committee from 2008–2018, which was tasked with the duty of implementing and communicating enterprise-wide risk management. From 2014 to 2022, Mr. Kadlec was on the board of the Futures Industry Association. In 2017, Mr. Kadlec was elected to the board of the National Futures Association. Mr. Kadlec has served as a Trustee of each First Trust Fund since its inception. Mr. Kadlec also served on the Executive Committee from the organization of the first First Trust closed-end fund in 2003 through 2005 (and 2014–2019) until he was elected as the first Lead Independent Trustee in December 2005, serving as such through 2007 (and 2014–2016). He also served as Chairman of the Valuation Committee (2008–2009 and 2017–2019), Chairman of the Audit Committee (2010–2011 and 2020–2022) and Chairman of the Nominating and Governance Committee (2012–2013). He currently serves as Vice Lead Independent Trustee (since March 12, 2024), on the Executive Committee (since March 12, 2024), on the Dividend Committee (since March 12, 2024) and as Chairman of the Nominating and Governance Committee (since January 1, 2023) of the First Trust Funds.

Denise M. Keefe has been Senior Vice President of Advocate Health, Continuing Health Division since 2023, and from 2018 to 2023 was Executive Vice President of Advocate Aurora Health (together, with Advocate Health, “Advocate”). Advocate is one of the largest integrated healthcare systems in the U.S. serving Illinois and Wisconsin. Ms. Keefe has been employed by Advocate since 1993 and is responsible for the Continuing Health Division’s strategic direction, fiscal management, business development, revenue enhancement, operational efficiencies, and human resource management of 4,000 employees. Ms. Keefe also currently serves on the boards of several organizations within the Advocate Aurora Continuing Health Division and other health care organizations, including RML Long Term Acute Care Hospitals (since 2014). Prior thereto, Ms. Keefe was Corporate Vice President, Marketing and Business Development for the Visiting Nurse Association of Chicago (1989–1992) and a former Board Member of Sherman West Court Skilled Nursing Facility. Ms. Keefe has served as a Trustee of the First Trust Funds and on the Audit Committee, Nominating and Governance Committee and Valuation Committee of the First Trust Funds since November 1, 2021. In addition, she currently serves as Audit Committee Vice Chair (since March 12, 2024) of the First Trust Funds.

Robert F. Keith is President of Hibs Enterprises, a financial and management consulting firm. Mr. Keith has been with Hibs Enterprises since 2003. Prior thereto, Mr. Keith spent 18 years with ServiceMaster and Aramark, including three years as President and COO of ServiceMaster Consumer Services, where he led the initial expansion of certain products overseas; five years as President and COO of ServiceMaster Management Services; and two years as President of Aramark ServiceMaster Management Services. Mr. Keith is a certified public accountant and also has held the positions of Treasurer and Chief Financial Officer of ServiceMaster, at which time he oversaw the financial aspects of ServiceMaster’s expansion of its Management Services division into Europe, the Middle East and Asia. Mr. Keith has served as a Trustee of the First Trust Funds since 2006. Mr. Keith has also served as the Chairman of the Audit Committee (2008–2009 and 2017–2019), Chairman of the Nominating and Governance Committee (2010–2011 and 2020–2022) and Chairman of the Valuation Committee (2014–2016) of the First Trust Funds. He served as Lead Independent Trustee and on the Executive Committee (2012–2016). He currently serves as Lead Independent Trustee and on the Executive Committee (since January 1, 2023) and as Chairman of the Dividend Committee (since January 1, 2023) of the First Trust Funds.

Niel B. Nielson, Ph.D., has been the Senior Advisor of Pelita Harapan Educational Foundation, a global provider of educational products and services since 2018. Prior thereto, Mr. Nielson served as the Managing Director and Chief Operating Officer of Pelita Harapan Educational Foundation for three years. Mr. Nielson formerly served as the President and Chief Executive Officer of Dew Learning LLC from 2012 through 2014. Mr. Nielson formerly served as President of Covenant College (2002–2012), and as a partner and trader (of options and futures contracts for hedging options) for Ritchie Capital Markets Group (1996–1997), where he held an administrative management position at this proprietary derivatives trading company. He also held prior positions in new business development for ServiceMaster Management Services Company and in personnel and human resources for NationsBank of North Carolina, N.A. and Chicago Research and Trading Group, Ltd. (“CRT”). His international experience includes serving as a director of CRT Europe, Inc. for two years, directing out of London

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all aspects of business conducted by the U.K. and European subsidiary of CRT. Prior to that, Mr. Nielson was a trader and manager at CRT in Chicago. Mr. Nielson has served as a Trustee of each First Trust Fund since its inception and of the First Trust Funds since 1999. Mr. Nielson has also served as Chairman of the Audit Committee (2003–2007 and 2014–2016), Chairman of the Valuation Committee (2012–2013), Chairman of the Nominating and Governance Committee (2008–2009 and 2017–2019), Chairman of the Dividend Committee (2020–2022), and Lead Independent Trustee (2010–2011 and 2020–2022) of the First Trust Funds. Further, he has served as a member of the Executive Committee (2010–2011 and January 1, 2020 – March 12, 2024) and the Dividend Committee (October 19, 2020 – March 12, 2024) of the First Trust Funds. He currently serves as Chairman of the Valuation Committee (since January 1, 2023) of the First Trust Funds.

Bronwyn Wright has acted as an independent director to a number of Irish collective investment funds since 2009. Ms. Wright is a former Managing Director of Citibank Europe plc and Head of Securities and Fund Services for Citi Ireland. In these positions, she was responsible for the management and strategic direction of Citi Ireland’s securities and fund services business which included funds, custody, security finance/lending and global agency and trust. She also had responsibility for leading, managing and growing the Trustee, Custodian and Depositary business in Ireland, the United Kingdom, Luxembourg, Jersey and Cayman. Ms. Wright has served as a Trustee of the First Trust Funds and on the Audit Committee, Nominating and Governance Committee and Valuation Committee of the First Trust Funds since September 10, 2023.

James A. Bowen is Chief Executive Officer of First Trust Advisors L.P. and First Trust Portfolios L.P. Mr. Bowen is involved in the day-to-day management of the First Trust Funds and serves on the Executive Committee. He has over 35 years of experience in the investment company business in sales, sales management and executive management. Mr. Bowen has served as a Trustee of each First Trust Fund since its inception and of the First Trust Funds since 1999.

Effective January 1, 2024, the fixed annual retainer paid to the Independent Trustees is $285,000 per year and an annual per fund fee of $7,500 for each closed-end fund, $2,000 for each actively managed fund, $750 for each target outcome fund and $500 for each index fund. The fixed annual retainer is allocated equally among each fund in the First Trust Fund Complex rather than being allocated pro rata based on each fund’s net assets. Additionally, the Lead Independent Trustee is paid $30,000 annually, the Vice Lead Independent Trustee is paid up to $25,000 annually (effective March 12, 2024), the Chairman of the Audit Committee is paid $25,000 annually, the Chairman of the Valuation Committee is paid $20,000 annually, the Chairman of the Nominating and Governance Committee is paid $20,000 annually and the Vice Chair of the Audit Committee is paid $15,000 annually (effective March 12, 2024) to serve in such capacities with compensation allocated pro rata among each fund in the First Trust Fund Complex based on its net assets. Trustees are also reimbursed by the funds in the First Trust Fund Complex for travel and out-of-pocket expenses incurred in connection with all meetings. Each Committee Chair, the Audit Committee Vice Chair, the Lead Independent Trustee and the Vice Lead Independent Trustee rotate in accordance with the rotation periods established by the Board.

The following table sets forth the total compensation (including reimbursement for travel and out-of-pocket expenses) paid by the Funds and the First Trust Fund Complex to each of the Independent Trustees for the fiscal year ended July 31, 2024 and the calendar year ended December 31, 2023, respectively. The Trust has no retirement or pension plans. The officers and Trustee who are “interested persons” as designated above serve without any compensation from the Trust. The Trust has no employees. Its officers are compensated by First Trust. 

Name of Trustee	Total Compensation from the Funds (1)	Total Compensation from the First Trust Fund Complex (2)
Richard E. Erickson	$31,950	$572,000
Thomas R. Kadlec	$32,039	$567,000
Denise M. Keefe	$29,920	$547,000
Robert F. Keith	$32,424	$577,000
Niel B. Nielson	$31,477	$567,000
Bronwyn Wright	$31,924	$274,250

(1)

The compensation paid by the Funds to the Independent Trustees for the fiscal year ended July 31, 2024 for services to the Funds.

(2)

The total compensation paid to the Independent Trustees for the calendar year ended December 31, 2023 for services to the 262 portfolios existing in 2023, which consisted of 11 open-end mutual funds, 14 closed-end funds and 237 exchange-traded funds.

The following table sets forth the dollar range of equity securities beneficially owned by the Trustees in the Funds and in other funds overseen by the Trustees in the First Trust Fund Complex as of December 31, 2023:

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Dollar Range of Equity Securities in the Funds 

	Interested Trustee	Independent Trustees
	James A. Bowen	Richard E. Erickson	Thomas R. Kadlec	Denise M. Keefe	Robert F. Keith	Niel B. Nielson	Bronwyn Wright
First Trust Energy AlphaDEX® Fund	Over $100,000	None	None	None	None	None	None
First Trust Financials AlphaDEX® Fund	Over $100,000	None	None	None	None	None	None
First Trust Health Care AlphaDEX® Fund	None	None	None	$50,001– $100,000	None	None	None
First Trust Materials AlphaDEX® Fund	None	None	None	None	None	$10,001– $50,000	None
First Trust Large Cap Core AlphaDEX® Fund	Over $100,000	None	None	None	Over $100,000	None	None
First Trust Large Cap Value AlphaDEX® Fund	Over $100,000	None	None	None	None	None	None
First Trust Mid Cap Core AlphaDEX® Fund	None	None	None	None	$10,001– $50,000	None	None
First Trust Multi Cap Growth AlphaDEX® Fund	None	None	None	None	$50,001– $100,000	$10,001– $50,000	None
First Trust Multi Cap Value AlphaDEX® Fund	Over $100,000	None	None	$10,001– $50,000	$10,001– $50,000	None	None
First Trust Small Cap Core AlphaDEX® Fund	Over $100,000	None	None	None	$10,001– $50,000	None	None
First Trust Small Cap Growth AlphaDEX® Fund	None	None	None	None	None	$10,001– $50,000	None
Aggregate Dollar Range of Equity Securities in All Registered Investment Companies Overseen by Trustee in First Trust Fund Complex	Over $100,000	Over $100,000	Over $100,000	Over $100,000	Over $100,000	Over $100,000	None

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As of October 31, 2024, the Independent Trustees of the Trust and their immediate family members did not own beneficially or of record any class of securities of an investment advisor or principal underwriter of the Funds or any person directly or indirectly controlling, controlled by or under common control with an investment advisor or principal underwriter of the Funds.

As of October 31, 2024, the officers and Trustees, in the aggregate, owned less than 1% of the shares of each Fund.

The table set forth in Exhibit A shows the percentage ownership of each shareholder or “group” (as that term is used in Section 13(d) of the 1934 Act) who, based on the securities position listing reports as of October 31, 2024, owned of record, or is known by the Trust to have owned of record or beneficially, 5% or more of the shares of a Fund (the “Principal Holders”). A control person is one who owns, either directly or indirectly, more than 25% of the voting securities of a Fund or acknowledges the existence of control. A party that controls a Fund may be able to significantly influence the outcome of any item presented to shareholders for approval. The Funds do not have any knowledge of who the ultimate beneficiaries are of the shares.

Investment Advisor. First Trust, 120 East Liberty Drive, Suite 400, Wheaton, Illinois 60187, is the investment advisor to the Funds. First Trust is a limited partnership with one limited partner, Grace Partners of DuPage L.P., and one general partner, The Charger Corporation. Grace Partners of DuPage L.P. is a limited partnership with one general partner, The Charger Corporation, and a number of limited partners. The Charger Corporation is an Illinois corporation controlled by James A. Bowen, the Chief Executive Officer of First Trust. First Trust discharges its responsibilities to the Funds subject to the policies of the Funds.

First Trust provides investment tools and portfolios for advisors and investors. First Trust is committed to theoretically sound portfolio construction and empirically verifiable investment management approaches. Its asset management philosophy and investment discipline are deeply rooted in the application of intuitive factor analysis and model implementation to enhance investment decisions.

First Trust acts as investment advisor for the Funds and manages the investment and reinvestment of the assets of the Funds. First Trust also administers the Trust’s business affairs, provides office facilities and equipment and certain clerical, bookkeeping and administrative services, and permits any of its officers or employees to serve without compensation as Trustees or officers of the Trust if elected to such positions.

Pursuant to an investment management agreement between First Trust and the Trust (the “Expense Cap Investment Management Agreement”), on behalf of First Trust Consumer Discretionary AlphaDEX® Fund, First Trust Consumer Staples AlphaDEX® Fund, First Trust Energy AlphaDEX® Fund, First Trust Financials AlphaDEX® Fund, First Trust Health Care AlphaDEX® Fund, First Trust Industrials/Producer Durables AlphaDEX® Fund, First Trust Materials AlphaDEX® Fund, First Trust Technology AlphaDEX® Fund, First Trust Utilities AlphaDEX® Fund, First Trust Large Cap Core AlphaDEX® Fund, First Trust Large Cap Growth AlphaDEX® Fund, First Trust Large Cap Value AlphaDEX® Fund, First Trust Mid Cap Core AlphaDEX® Fund, First Trust Multi Cap Growth AlphaDEX® Fund, First Trust Multi Cap Value AlphaDEX® Fund and First Trust Small Cap Core AlphaDEX® Fund (each an “Expense Cap Fund”), First Trust manages the investment of each Expense Cap Fund's assets and is paid an annual management fee equal to 0.50% of such Fund’s average daily net assets.

Each Expense Cap Fund is responsible for all its expenses, including the investment advisory fees, costs of transfer agency, custody, fund administration, legal, audit and other services, interest, taxes, sublicensing fees, brokerage commissions and other expenses connected with executions of portfolio transactions, any distribution and service fees pursuant to a 12b-1 plan, if any, and extraordinary expenses. First Trust has agreed to waive fees and/or pay Expense  Cap  Fund expenses to the extent necessary to prevent the operating expenses of each Expense  Cap  Fund (excluding interest expense, brokerage commissions and other trading expenses, acquired fund fees and expenses, taxes and extraordinary expenses) from exceeding 0.70% of average daily net assets until November 30, 2025.

Pursuant to an investment management agreement between First Trust and the Trust (the "Unitary Fee Investment Management Agreement"), on behalf of First Trust Mid Cap Growth AlphaDEX® Fund, First Trust Mid Cap Value AlphaDEX® Fund, First Trust Small Cap Growth AlphaDEX® Fund and First Trust Small Cap Value AlphaDEX® Fund (each a “Unitary Fee Fund”), First Trust manages the investment of each Unitary Fee Fund's assets and is paid an annual unitary management fee of 0.70% of such Unitary Fee Fund’s average daily net assets and is responsible for the expenses of such Unitary Fee Fund, including the cost of transfer agency, custody, fund administration, legal, audit and other services, and excluding fee payments under the Unitary Fee Investment Management Agreement, distribution and service fees pursuant to a 12b-1 plan, if any, brokerage expenses, acquired fund fees and expenses, taxes, interest and extraordinary expenses.

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Under the Investment Management Agreements, First Trust shall not be liable for any loss sustained by reason of the purchase, sale or retention of any security, whether or not such purchase, sale or retention shall have been based upon the investigation and research made by any other individual, firm or corporation, if such recommendation shall have been selected with due care and in good faith, except loss resulting from willful misfeasance, bad faith, or gross negligence on the part of First Trust in the performance of its obligations and duties, or by reason of its reckless disregard of its obligations and duties. Each Investment Management Agreement terminates automatically upon assignment and is terminable at any time without penalty as to a Fund by the Board of Trustees, including a majority of the Independent Trustees, or by vote of the holders of a majority of the Fund’s outstanding voting securities on 60 days’ written notice to First Trust, or by First Trust on 60 days’ written notice to the Fund.

As approved by the Trust’s Board of Trustees, the management fee paid to the Advisor for each Expense Cap Fund will be reduced at certain levels of Fund net assets (“breakpoints”) and calculated pursuant to the schedule below: 

Management Fee	Breakpoints
0.50000%	Fund net assets up to and including $2.5 billion
0.48750%	Fund net assets greater than $2.5 billion up to and including $5 billion
0.47500%	Fund net assets greater than $5 billion up to and including $7.5 billion
0.46250%	Fund net assets greater than $7.5 billion up to and including $10 billion
0.45000%	Fund net assets greater than $10 billion up to and including $15 billion
0.42500%	Fund net assets greater than $15 billion

As approved by the Trust’s Board of Trustees, the management fee paid to the Advisor for each Unitary Fee Fund will be reduced at certain levels of Fund net assets (“breakpoints”) and calculated pursuant to the schedule below: 

Management Fee	Breakpoints
0.70000%	Fund net assets up to and including $2.5 billion
0.68250%	Fund net assets greater than $2.5 billion up to and including $5 billion
0.66500%	Fund net assets greater than $5 billion up to and including $7.5 billion
0.64750%	Fund net assets greater than $7.5 billion up to and including $10 billion
0.63000%	Fund net assets greater than $10 billion up to and including $15 billion
0.59500%	Fund net assets greater than $15 billion

The following table sets forth the management fees (net of fee waivers and expense reimbursements, where applicable) paid by each Expense Cap Fund to First Trust, and the fees waived and expenses reimbursed by First Trust, for the specified periods. The second table sets forth the unitary management fee paid by each Unitary Fee Fund to First Trust for the specified periods. 

	Amount of Management Fees (Net of Fee Waivers and Expense Reimbursements by First Trust)			Amount of Fees Waived and Expenses Reimbursed By First Trust
Fund	Fiscal Year Ended July 31,			Fiscal Year Ended July 31,
	2024	2023	2022	2024	2023	2022
First Trust Consumer Discretionary AlphaDEX® Fund	$7,143,614	$3,441,623	$7,308,183	$0	$0	$0
First Trust Consumer Staples AlphaDEX® Fund	$2,425,698	$3,390,095	$1,930,852	$0	$0	$0
First Trust Energy AlphaDEX® Fund	$3,020,337	$6,597,347	$4,492,207	$0	$0	$0
First Trust Financials AlphaDEX® Fund	$4,080,340	$5,933,523	$7,077,467	$0	$0	$0
First Trust Health Care AlphaDEX® Fund	$6,420,544	$7,693,304	$7,523,292	$0	$0	$0

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	Amount of Management Fees (Net of Fee Waivers and Expense Reimbursements by First Trust)			Amount of Fees Waived and Expenses Reimbursed By First Trust
Fund	Fiscal Year Ended July 31,			Fiscal Year Ended July 31,
	2024	2023	2022	2024	2023	2022
First Trust Industrials/Producer Durables AlphaDEX® Fund	$8,842,921	$7,881,258	$8,639,335	$0	$0	$0
First Trust Large Cap Core AlphaDEX® Fund	$5,707,633	$5,576,924	$5,826,348	$0	$0	$0
First Trust Large Cap Growth AlphaDEX® Fund	$5,255,828	$4,601,151	$5,582,229	$0	$0	$0
First Trust Large Cap Value AlphaDEX® Fund	$5,824,352	$6,023,648	$5,745,159	$0	$0	$0
First Trust Materials AlphaDEX® Fund	$2,245,029	$7,037,988	$4,889,407	$0	$0	$0
First Trust Mid Cap Core AlphaDEX® Fund	$5,485,317	$4,914,374	$5,037,782	$0	$0	$0
First Trust Multi Cap Growth AlphaDEX® Fund	$899,049	$845,931	$1,119,691	$0	$0	$0
First Trust Multi Cap Value AlphaDEX® Fund	$784,357	$952,139	$819,696	$0	$0	$0
First Trust Small Cap Core AlphaDEX® Fund	$4,187,212	$3,997,433	$4,500,595	$0	$0	$0
First Trust Technology AlphaDEX® Fund	$6,422,504	$5,286,169	$9,453,163	$0	$0	$0
First Trust Utilities AlphaDEX® Fund	$1,188,606	$1,840,420	$1,195,958	$0	$0	$0

 

Amount of Unitary Fees
Fund	Fiscal Year Ended July 31,
	2024	2023	2022
First Trust Mid Cap Growth AlphaDEX® Fund	$2,107,552	$1,827,178	$2,582,890
First Trust Mid Cap Value AlphaDEX® Fund	$1,554,255	$1,654,492	$1,373,456
First Trust Small Cap Growth AlphaDEX® Fund	$1,745,212	$1,484,647	$2,055,987
First Trust Small Cap Value AlphaDEX® Fund	$1,234,173	$1,309,156	$1,659,766

Investment Committee. The Investment Committee of First Trust (the “Investment Committee”) is jointly and primarily responsible for the day-to-day management of the Funds. There are currently seven members of the Investment Committee, as follows: 

Name	Position with First Trust	Length of Service with First Trust	Principal Occupation During Past Five Years
Daniel J. Lindquist	Chairman of the Investment Committee and Managing Director	Since 2004	Managing Director, First Trust Advisors L.P. and First Trust Portfolios L.P.
David G. McGarel	Chief Operating Officer, Chief Investment Officer and Managing Director	Since 1997	Chief Operating Officer (2016 to present), Chief Investment Officer and Managing Director, First Trust Advisors L.P. and First Trust Portfolios L.P.
Jon C. Erickson	Senior Vice President	Since 1994	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.

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Name	Position with First Trust	Length of Service with First Trust	Principal Occupation During Past Five Years
Roger F. Testin	Senior Vice President	Since 2001	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.
Stan Ueland	Senior Vice President	Since 2005	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.
Chris A. Peterson	Senior Vice President	Since 2000	Senior Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.
Erik Russo	Vice President	Since 2010	Vice President, First Trust Advisors L.P. and First Trust Portfolios L.P.

Daniel J. Lindquist, CFA: Mr. Lindquist is Chairman of the Investment Committee and presides over Investment Committee meetings. Mr. Lindquist is also responsible for overseeing the implementation of the Funds' investment strategies.

David G. McGarel, CFA: As First Trust's Chief Investment Officer, Mr. McGarel consults with the Investment Committee on market conditions and First Trust's general investment philosophy. As Chief Operating Officer, Mr. McGarel is responsible for First Trust and FTP operations, including information systems, trust administration and First Trust administration.

Jon C. Erickson, CFA: As the head of First Trust’s Equity Research Group, Mr. Erickson is responsible for determining the securities to be purchased and sold by funds that do not utilize quantitative investment strategies.

Roger F. Testin, CFA: As head of First Trust’s Portfolio Management Group, Mr. Testin is responsible for executing the instructions of the Strategy Research Group and Equity Research Group.

Stan Ueland: Mr. Ueland is a Senior Vice President and is responsible for executing the investment strategies of the Funds.

Chris A. Peterson, CFA: Mr. Peterson is a Senior Vice President and head of the strategy research group at First Trust. Mr. Peterson is responsible for developing and implementing quantitative equity investment strategies.

Erik Russo:  Mr. Russo is a Vice President of First Trust. He is responsible for implementing the investment strategies of each portfolio of exchange-traded funds advised by First Trust in his role as a portfolio manager.

As of July 31, 2024, Mr. Lindquist, Mr. McGarel, Mr. Testin, Mr. Ueland, Mr. Peterson and Mr. Russo each beneficially owned shares of a Fund. Mr. Lindquist owned shares of First Trust Energy AlphaDEX® Fund in the amount of $50,001-$100,000, shares of First Trust Health Care AlphaDEX® Fund in the amount of $10,001–$50,000 and First Trust Large Cap Value AlphaDEX® Fund in the amount of $10,001–$50,000. Mr. McGarel owned shares of First Trust Energy AlphaDEX® Fund in the amount of over $100,000, shares of First Trust Financials AlphaDEX® Fund in the amount of $50,001–$100,000, shares of First Trust Health Care AlphaDEX® Fund in the amount of over $100,000, shares of First Trust Large Cap Core AlphaDEX® Fund in the amount of over $100,000, shares of First Trust Large Cap Growth AlphaDEX® Fund in the amount of over $100,000, shares of First Trust Large Cap Value AlphaDEX® Fund in the amount of over $100,000 and shares of First Trust Multi Cap Value AlphaDEX® Fund in the amount of over $100,000. Mr. Testin owned shares of First Trust Financials AlphaDEX® Fund in the amount of $10,001–$50,000, shares of First Trust Health Care AlphaDEX® Fund in the amount of $10,001–$50,000, shares of First Trust Mid Cap Core AlphaDEX® Fund in the amount of $10,001–$50,000, shares of First Trust Large Cap Growth AlphaDEX® Fund in the amount of $10,001–$50,000 and shares of First Trust Small Cap Core AlphaDEX® Fund in the amount of $10,001–$50,000. Mr. Ueland owned shares of First Trust Health Care AlphaDEX® Fund in the amount of $10,001–$50,000 and shares of First Trust Technology AlphaDEX® Fund in the amount of $50,001–$100,000. Mr. Peterson owned shares of First Trust Industrials/Producer Durables AlphaDEX® Fund in the amount of $10,001–$50,000, shares of First Trust Large Cap Core AlphaDEX® Fund in the amount of $50,001–$100,000, shares of First Trust Mid Cap Core AlphaDEX® Fund in the amount of $50,001–$100,000, shares of First Trust Large Cap Value AlphaDEX® Fund in the amount of over $100,000 and shares of First Trust Multi Cap Growth AlphaDEX® Fund in the amount of $10,001–$50,000. Mr. Russo owned shares of First Trust Energy AlphaDEX® Fund in the amount of $1–$10,000, shares of First Trust Large Cap Value AlphaDEX® Fund in the amount of $10,001–$50,000 and shares of First Trust Small Cap Value AlphaDEX® Fund in the amount of $1–$10,000.

Compensation. The compensation structure for each member of the Investment Committee is based upon a fixed salary as well as a discretionary bonus determined by the management of First Trust.  Salaries are determined by management and are based upon an individual’s position and overall value to the firm.  Bonuses are also determined by management and are based upon an individual’s overall contribution to the success of the firm and the profitability of the firm.  Salaries and bonuses for members of the Investment Committee are not based upon criteria such as performance of the Funds or the value of assets included in the Funds’ portfolios.  In addition Mr. Erickson, Mr. Lindquist, Mr. McGarel, Mr.

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Peterson and Mr. Ueland also have an indirect ownership stake in the firm and will therefore receive their allocable share of ownership-related distributions.

Accounts Managed by Investment Committee

The Investment Committee manages the investment vehicles (other than the Funds) with the number of accounts and assets, as of the fiscal year ended July 31, 2024, set forth in the table below: 

Investment Committee Member	Registered Investment Companies Number of Accounts ($ Assets in Thousands)	Other Pooled Investment Vehicles Number of Accounts ($ Assets in Thousands)	Other Accounts Number of Accounts ($ Assets in Thousands)	Registered Investment Companies With Performance Fees Number of Accounts ($ Assets in Thousands)	Other Pooled Investment Vehicles With Performance Fees Number of Accounts ($ Assets in Thousands)	Other Accounts With Performance Fees Number of Accounts ($ Assets in Thousands)
Daniel J. Lindquist	104 ($81,499,828)	50 ($2,682,933)	1,136 ($443,733)	N/A	N/A	N/A
David G. McGarel	105 ($81,534,197)	50 ($2,682,933)	1,136 ($443,733)	N/A	N/A	N/A
Jon C. Erickson	101 ($81,490,418)	50 ($2,682,933)	1,136 ($443,733)	N/A	N/A	N/A
Roger F. Testin	101 ($81,490,418)	50 ($2,682,933)	1,136 ($443,733)	N/A	N/A	N/A
Stan Ueland	95 ($80,399,344)	43 ($2,530,742)	N/A	N/A	N/A	N/A
Chris A. Peterson	105 ($81,534,197)	50 ($2,682,933)	1,136 ($443,733)	N/A	N/A	N/A
Erik Russo	95 ($80,399,344)	43 ($2,530,742)	N/A	N/A	N/A	N/A

Conflicts. None of the accounts managed by the Investment Committee pay an advisory fee that is based upon the performance of the account. In addition, First Trust believes that there are no material conflicts of interest that may arise in connection with the Investment Committee's management of the Funds' investments and the investments of the other accounts managed by the Investment Committee. However, because the investment strategy of the Funds and the investment strategies of many of the other accounts managed by the Investment Committee are based on fairly mechanical investment processes, the Investment Committee may recommend that certain clients sell and other clients buy a given security at the same time. In addition, because the investment strategies of the Funds and other accounts managed by the Investment Committee generally result in the clients investing in readily available securities, First Trust believes that there should not be material conflicts in the allocation of investment opportunities between the Funds and other accounts managed by the Investment Committee.

Brokerage Allocations

First Trust is responsible for decisions to buy and sell securities for the Funds and for the placement of the Funds’ securities business, the negotiation of the commissions to be paid on brokered transactions, the prices for principal trades in securities, and the allocation of portfolio brokerage and principal business. It is the policy of First Trust to seek the best execution at the best security price available with respect to each transaction, and with respect to brokered transactions in light of the overall quality of brokerage and research services provided to First Trust and its clients. The best price to a Fund means the best net price without regard to the mix between purchase or sale price and commission, if any. Purchases may be made from underwriters, dealers and, on occasion, the issuers. Commissions will be paid on a Fund’s futures and options transactions, if any. The purchase price of portfolio securities purchased from an underwriter or dealer may include underwriting commissions and dealer spreads. The Funds may pay markups on principal transactions. In selecting broker-dealers and in negotiating commissions, First Trust considers, among other things, the firm’s reliability, the quality of its execution services on a continuing basis and its financial condition. Fund portfolio transactions may be effected with broker-dealers who have assisted investors in the purchase of shares.

Section 28(e) of the 1934 Act permits an investment advisor, under certain circumstances, to cause an account to pay a broker or dealer who supplies brokerage and research services a commission for effecting a transaction in excess of the amount of commission another broker or dealer would have charged for effecting the transaction. Brokerage and research services include (a) furnishing advice as to the value of securities, the advisability of investing, purchasing or selling securities, and the availability of securities or purchasers or sellers of securities; (b) furnishing analyses and reports concerning issuers, industries, securities, economic factors and trends, portfolio strategy and the performance of accounts;

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and (c) effecting securities transactions and performing functions incidental thereto (such as clearance, settlement and custody). Such brokerage and research services are often referred to as “soft dollars.” First Trust has advised the Board of Trustees that it does not currently intend to use soft dollars.

Notwithstanding the foregoing, in selecting brokers, First Trust may in the future consider investment and market information and other research, such as economic, securities and performance measurement research, provided by such brokers, and the quality and reliability of brokerage services, including execution capability, performance and financial responsibility.

Accordingly, the commissions charged by any such broker may be greater than the amount another firm might charge if First Trust determines in good faith that the amount of such commissions is reasonable in relation to the value of the research information and brokerage services provided by such broker to First Trust or the Trust. In addition, First Trust must determine that the research information received in this manner provides the Funds with benefits by supplementing the research otherwise available to the Funds. The Investment Management Agreements provide that such higher commissions will not be paid by the Funds unless the Advisor determines in good faith that the amount is reasonable in relation to the services provided. The investment advisory fees paid by the Funds to First Trust under the Investment Management Agreements would not be reduced as a result of receipt by First Trust of research services.

First Trust places portfolio transactions for other advisory accounts advised by it, and research services furnished by firms through which the Funds effect their securities transactions may be used by First Trust in servicing all of its accounts; not all of such services may be used by First Trust in connection with the Funds. First Trust believes it is not possible to measure separately the benefits from research services to each of the accounts (including the Funds) advised by it. Because the volume and nature of the trading activities of the accounts are not uniform, the amount of commissions in excess of those charged by another broker paid by each account for brokerage and research services will vary. However, First Trust believes such costs to the Funds will not be disproportionate to the benefits received by the Funds on a continuing basis. First Trust seeks to allocate portfolio transactions equitably whenever concurrent decisions are made to purchase or sell securities by the Funds and another advisory account. In some cases, this procedure could have an adverse effect on the price or the amount of securities available to the Funds. In making such allocations between the Funds and other advisory accounts, the main factors considered by First Trust are the respective investment objectives, the relative size of portfolio holding of the same or comparable securities, the availability of cash for investment and the size of investment commitments generally held.

Brokerage Commissions

The following table sets forth the aggregate amount of brokerage commissions paid by each Fund for the specified periods. Significant variations in the amount a Fund paid in brokerage commissions from year-to-year are generally the result of fluctuations in the size of a Fund or changes to a Fund’s portfolio holdings. 

Aggregate Amount of Brokerage Commissions
Fund	Fiscal Year Ended July 31,
	2024	2023	2022
First Trust Consumer Discretionary AlphaDEX® Fund	$656,221	$423,135	$436,187
First Trust Consumer Staples AlphaDEX® Fund	$115,351	$140,359	$130,999
First Trust Energy AlphaDEX® Fund	$255,039	$416,070	$452,188
First Trust Financials AlphaDEX® Fund	$312,737	$445,821	$449,775
First Trust Health Care AlphaDEX® Fund	$462,855	$528,885	$305,176
First Trust Industrials/Producer Durables AlphaDEX® Fund	$368,757	$423,653	$345,149
First Trust Large Cap Core AlphaDEX® Fund	$278,800	$276,462	$230,191
First Trust Large Cap Growth AlphaDEX® Fund	$262,035	$269,341	$239,523
First Trust Large Cap Value AlphaDEX® Fund	$350,461	$370,448	$271,761
First Trust Materials AlphaDEX® Fund	$129,955	$175,344	$263,277
First Trust Mid Cap Core AlphaDEX® Fund	$604,929	$564,941	$420,344
First Trust Mid Cap Growth AlphaDEX® Fund	$176,923	$175,066	$199,563

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Aggregate Amount of Brokerage Commissions
Fund	Fiscal Year Ended July 31,
	2024	2023	2022
First Trust Mid Cap Value AlphaDEX® Fund	$140,801	$149,936	$87,878
First Trust Multi Cap Growth AlphaDEX® Fund	$102,643	$104,939	$99,262
First Trust Multi Cap Value AlphaDEX® Fund	$79,357	$102,400	$62,165
First Trust Small Cap Core AlphaDEX® Fund	$1,036,226	$951,039	$692,420
First Trust Small Cap Growth AlphaDEX® Fund	$403,545	$325,180	$309,574
First Trust Small Cap Value AlphaDEX® Fund	$203,610	$229,180	$183,585
First Trust Technology AlphaDEX® Fund	$516,376	$410,877	$568,362
First Trust Utilities AlphaDEX® Fund	$74,286	$83,080	$50,780

During the last fiscal year, the First Trust Financials AlphaDEX® Fund held securities of BofA Securities, Inc., Goldman Sachs & Co. LLC and J.P. Morgan Securities LLC, each a regular broker or dealer of the Fund as defined in Rule 10b-1 under the 1940 Act. As of July 31, 2024, the Fund’s investment in each was 0.59%, 1.72% and 0.31% of the Fund’s net assets, respectively.

During the last fiscal year, the First Trust Large Cap Core AlphaDEX® Fund held securities of BofA Securities, Inc., Goldman Sachs & Co. LLC and J.P. Morgan Securities LLC, each a regular broker or dealer of the Fund as defined in Rule 10b-1 under the 1940 Act. As of July 31, 2024, the Fund’s investment in each was 0.26%, 029% and 0.45% of the Fund’s net assets, respectively.

During the last fiscal year, the First Trust Large Cap Growth AlphaDEX® Fund held securities of J.P. Morgan Securities LLC, a regular broker or dealer of the Fund as defined in Rule 10b-1 under the 1940 Act. As of July 31, 2024, the Fund’s investment was 0.94% of the Fund's net assets.

During the last fiscal year, the First Trust Large Cap Value AlphaDEX® Fund held securities of BofA Securities, Inc., Goldman Sachs & Co. LLC and J.P. Morgan Securities LLC, each a regular broker or dealer of the Fund as defined in Rule 10b-1 under the 1940 Act. As of July 31, 2024, the Fund’s investment in each was 0.50%, 0.38% and 0.00% of the Fund’s net assets, respectively.

During the last fiscal year, the First Trust Multi Cap Value AlphaDEX® Fund held securities of BofA Securities, Inc. and J.P. Morgan Securities LLC, each a regular broker or dealer of the Fund as defined in Rule 10b-1 under the 1940 Act. As of July 31, 2024, the Fund’s investment in each was 0.25% and 0.00% of the Fund’s net assets, respectively.

Administrator, Fund Accounting Agent, Custodian, Transfer Agent, Distributor, Index Providers and Exchanges

Administrator and Fund Accounting Agent. The Trust has appointed the Bank of New York Mellon (“BNY”), located at 240 Greenwich Street, New York, New York 10286, to serve as the Funds’ administrator and provide the Funds with accounting services pursuant to a fund administration and accounting agreement (the “Administration and Accounting Agreement”). Under the Administration and Accounting Agreement, BNY is obligated, on a continuous basis, to provide such administrative services as the Board reasonably deems necessary for the proper administration of the Trust and the Funds. BNY generally will assist in many aspects of the Trust’s and the Funds’ operations, including accounting, bookkeeping and record keeping services (including, without limitation, the maintenance of such books and records as are required under the 1940 Act and the rules thereunder, except as maintained by other service providers), assist in preparing reports to shareholders or investors, prepare and file tax returns, supply financial information and supporting data for reports to and filings with the SEC and various state Blue Sky authorities and supply supporting documentation for meetings of the Board.

Custodian. The Trust has appointed BNY to serve as the Funds’ custodian pursuant to a custody agreement (the “Custody Agreement”). Pursuant to the terms of the Custody Agreement, BNY is generally responsible for the safekeeping of the Funds’ assets and performing various other administrative duties set forth in the Custody Agreement.

Transfer Agent. The Trust has appointed BNY to serve as the Funds’ transfer agent and dividend disbursing agent pursuant to a transfer agency and service agreement (the “Transfer Agency Agreement”). Pursuant to the terms of the

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Transfer Agency Agreement, BNY is responsible for performing and facilitating the purchases and redemptions of Creation Unit Aggregations, as well as performing other customary services of a transfer agent and dividend disbursing agent.

As set forth in the Administration and Accounting Agreement, Custody Agreement and Transfer Agency Agreement, the Trust, on behalf of each Fund, has agreed to indemnify and hold harmless BNY from certain costs, expenses, damages, liabilities or claims which are sustained or incurred or which may be asserted against BNY, provided that such costs, expenses, damages, liabilities and claims did not result from BNY’s own negligence or willful misconduct.

As compensation for the services provided by BNY under the Administration and Accounting Agreement, Custody Agreement and Transfer Agency Agreement, the Trust, on behalf of each Fund, has agreed to pay to BNY such compensation as may be specifically agreed upon from time to time and reimburse BNY for out-of-pocket expenses which are a normal incident of the services provided under the agreements. Pursuant to the terms of the Unitary Fee Investment Management Agreement, the Unitary Fee Funds do not directly pay BNY for these services, as First Trust has assumed responsibility for the payment of these expenses out of the unitary management fee it receives from such Unitary Fee Funds. Each Expense Cap Fund is responsible for the payment of these expenses. The following table sets forth the amounts paid by each Expense Cap Fund to BNY for the specified periods. 

Fund Administration and Accounting
Fund	Fiscal Year Ended July 31,
	2024	2023	2022
First Trust Consumer Discretionary AlphaDEX® Fund	$591,492	$335,085	$671,727
First Trust Consumer Staples AlphaDEX® Fund	$212,178	$340,314	$194,358
First Trust Energy AlphaDEX® Fund	$248,032	$613,493	$425,195
First Trust Financials AlphaDEX® Fund	$339,302	$573,363	$667,726
First Trust Health Care AlphaDEX® Fund	$523,610	$716,990	$703,280
First Trust Industrials/Producer Durables AlphaDEX® Fund	$702,021	$732,206	$792,790
First Trust Large Cap Core AlphaDEX® Fund	$481,861	$548,418	$568,235
First Trust Large Cap Growth AlphaDEX® Fund	$450,346	$461,698	$545,026
First Trust Large Cap Value AlphaDEX® Fund	$489,041	$583,589	$561,220
First Trust Materials AlphaDEX® Fund	$175,476	$658,919	$461,817
First Trust Mid Cap Core AlphaDEX® Fund	$469,918	$493,417	$504,080
First Trust Multi Cap Growth AlphaDEX® Fund	$85,053	$89,075	$115,993
First Trust Multi Cap Value AlphaDEX® Fund	$75,003	$99,441	$85,504
First Trust Small Cap Core AlphaDEX® Fund	$365,347	$404,154	$453,760
First Trust Technology AlphaDEX® Fund	$524,710	$523,836	$847,874
First Trust Utilities AlphaDEX® Fund	$105,351	$185,318	$120,835

Distributor. First Trust Portfolios L.P., an affiliate of First Trust, is the distributor and principal underwriter of the shares of the Funds. Its principal address is 120 East Liberty Drive, Suite 400, Wheaton, Illinois 60187. The Distributor has entered into a Distribution Agreement with the Trust pursuant to which it distributes Fund shares.  Shares are continuously offered for sale by Funds through the Distributor only in Creation Unit Aggregations, as described in the Prospectus under the heading "Other Information - Continuous Offering."

For the fiscal years ended July 31, 2022, July 31, 2023 and July 31, 2024, there were no underwriting commissions with respect to the sale of Fund shares and FTP did not receive compensation on redemptions for the Funds for those periods.

12b-1 Plan. The Trust has adopted a Plan of Distribution pursuant to Rule 12b-1 under the 1940 Act (the “Plan”) pursuant to which the Funds may reimburse the Distributor up to a maximum annual rate of 0.25% of their average daily net assets.

Under the Plan and as required by Rule 12b-1, the Trustees will receive and review after the end of each calendar quarter a written report provided by the Distributor of the amounts expended under the Plan and the purpose for which such expenditures were made. With the exception of the Distributor and its affiliates, no “interested person” of the Trust (as that

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term is defined in the 1940 Act) and no Trustee of the Trust has a direct or indirect financial interest in the operation of the Plan or any related agreement.

No fee is currently paid by the Funds under the Plan and, pursuant to a contractual agreement, the Funds will not pay 12b-1 fees any time before November 30, 2025.

Aggregations. Fund shares in less than Creation Unit Aggregations are not distributed by the Distributor. The Distributor will deliver the Prospectus and, upon request, this SAI to persons purchasing Creation Unit Aggregations and will maintain records of both orders placed with it and confirmations of acceptance furnished by it. The Distributor is a broker-dealer registered under the 1934 Act and a member of the Financial Industry Regulatory Authority (“FINRA”).

The Distribution Agreement provides that it may be terminated at any time, without the payment of any penalty, on at least 60 days’ written notice by the Trust to the Distributor (i) by vote of a majority of the Independent Trustees or (ii) by vote of a majority of the outstanding voting securities (as defined in the 1940 Act) of the Funds. The Distribution Agreement will terminate automatically in the event of its assignment (as defined in the 1940 Act).

The Distributor has entered into agreements with securities dealers ("Soliciting Dealers") who will solicit purchases of Creation Unit Aggregations of Fund shares.  Such Soliciting Dealers may also be Participating Parties (as defined in "Procedures for Creation of Creation Unit Aggregations" below) and DTC Participants (as defined in "DTC Acts as Securities Depository for Fund Shares" below).

Index Providers.  The Indices that each of the AlphaDEX® Sector Funds seeks to track are compiled by IDI Indices, LLC. The Indices that each of the AlphaDEX® Style Funds seeks to track are compiled by Nasdaq, Inc. First Trust does not guarantee the accuracy and/or the completeness of the Indices or any data included therein, and First Trust shall have no liability for any errors, omissions or interruptions therein. First Trust makes no warranty, express or implied, as to results to be obtained by a Fund, owners of the shares of a Fund or any other person or entity from the use of an Index or any data included therein. First Trust makes no express or implied warranties, and expressly disclaims all warranties of merchantability or fitness for a particular purpose or use with respect to the Indices or any data included therein. Without limiting any of the foregoing, in no event shall First Trust have any liability for any special, punitive, direct, indirect or consequential damages (including lost profits) arising out of matters relating to the use of the Indices, even if notified of the possibility of such damages.

AlphaDEX® Sector Funds.   Source IDI Indices, LLC (“IDI”), is used with permission. “StrataQuant®” is a service/trade mark of IDI or its affiliates. Frank Russell Company is the source and owner of the trademarks, service marks and copyrights related to the Russell Indexes. Russell®, Russell 1000® and Russell 3000® are all registered trademarks of Frank Russell Company. Russell 1000® and Russell 3000® are being utilized in the Indices under license. These trademarks have been licensed, along with the StrataQuant® Consumer Discretionary Index, the StrataQuant® Consumer Staples Index, the StrataQuant® Energy Index, the StrataQuant® Financial Index, the StrataQuant® Health Care Index, the StrataQuant® Industrials Index, the StrataQuant® Materials Index, the StrataQuant® Technology Index and the StrataQuant® Utilities Index, (each an “Index,” collectively the "Indices") for use by FTP in connection with the First Trust Consumer Discretionary AlphaDex® Fund (FXD), the First Trust Consumer Staples AlphaDEX® Fund (FXG), the First Trust Energy AlphaDEX® Fund (FXN), the First Trust Financials AlphaDEX® Fund (FXO), the First Trust Health Care AlphaDEX® Fund (FXH), the First Trust Industrials/Producer Durables AlphaDEX® Fund (FXR), the First Trust Materials AlphaDEX® Fund (FXZ), First Trust Technology AlphaDEX® Fund (FXL), and the First Trust Utilities AlphaDEX® Fund (FXU) (each the “Product”). Neither FTP, First Trust Exchange-Traded AlphaDEX® Fund (the “Trust”) nor the Product, as applicable, is sponsored, endorsed, sold or promoted by IDI Indices, LLC, its affiliates or its Third Party Suppliers including without limitation Frank Russell Company (“IDI and its Suppliers”). IDI and its Suppliers make no representations or warranties regarding the advisability of investing in securities generally, in the Product particularly, the Trust or the ability of the Index to track general stock market performance. IDI’s only relationship to FTP is the licensing of certain trademarks and trade names and the Index or components thereof. The Index is determined, composed and calculated by IDI without regard to the Licensee or the Product or its holders. IDI has no obligation to take the needs of the Licensee or the holders of the Product into consideration in determining, composing or calculating the Index. IDI is not responsible for and has not participated in the determination of the timing of, prices of, or quantities of the Product to be issued or in the determination or calculation of the equation by which the Product is to be priced, sold, purchased, or redeemed. Except for certain custom index calculation services, all information provided by IDI is general in nature and not tailored to the needs of Licensee or any other person, entity or group of persons. IDI has no obligation or liability in connection with the administration, marketing, or trading of the Product. IDI is not an investment advisor. Inclusion of a security within an index is not a recommendation by IDI to buy, sell, or hold such security, nor is it considered to be investment advice. FTP has licensed to IDI, free of charge, the right to use certain

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intellectual property owned by FTP, including the AlphaDEX® trademark and the AlphaDEX® stock selection method, in connection with the creation of the StrataQuant® Series Indices. FTP has received a patent on the AlphaDEX® stock selection method from the United States Patent and Trademark Office. Notwithstanding such license, IDI is solely responsible for the creation, compilation and administration of the StrataQuant® Series Indices and has the exclusive right to determine the stocks included in the Indices and the Indices’ methodologies.

IDI AND ITS SUPPLIERS DISCLAIM ANY AND ALL WARRANTIES AND REPRESENTATIONS, EXPRESS AND/OR IMPLIED, INCLUDING ANY WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE, INCLUDING THE INDICES, INDEX DATA AND ANY INFORMATION INCLUDED IN, RELATED TO, OR DERIVED THEREFROM (“INDEX DATA”). IDI AND ITS SUPPLIERS SHALL NOT BE SUBJECT TO ANY DAMAGES OR LIABILITY WITH RESPECT TO THE ADEQUACY, ACCURACY, TIMELINESS OR COMPLETENESS OF THE INDICES AND THE INDEX DATA, WHICH ARE PROVIDED ON AN “AS IS” BASIS AND YOUR USE IS AT YOUR OWN RISK.

AlphaDEX® Style Funds.   FTP has licensed to Nasdaq, Inc., free of charge, the right to use certain intellectual property owned by FTP, including the AlphaDEX® trademark and the AlphaDEX® stock selection method, in connection with Nasdaq Inc.’s creation of certain Indices. Notwithstanding such license, Nasdaq, Inc. is solely responsible for the creation, compilation and administration of such Indices and has the exclusive right to determine the stocks included in the Indices and the Indices’ methodologies.

The AlphaDEX® Style Funds are not sponsored, endorsed, sold or promoted by Nasdaq, Inc. or its affiliates (Nasdaq, Inc., with its affiliates, are referred to as the “Corporations”). The Corporations have not passed on the legality or suitability of, or the accuracy or adequacy of descriptions and disclosures relating to, the AlphaDEX® Style Funds. The Corporations make no representation or warranty, express or implied to the owners of the AlphaDEX® Style Funds or any member of the public regarding the advisability of investing in securities generally or in the AlphaDEX® Style Funds particularly, or the ability of the Indices to track general stock market performance. The Corporations’ only relationship to First Trust is in the licensing of “Nasdaq,” and the Indices’ registered trademarks, trade names and service marks of the Corporations and the use of the Indices which is determined, composed and calculated by Nasdaq, Inc. without regard to First Trust or the AlphaDEX® Style Funds. Nasdaq, Inc. has no obligation to take the needs of First Trust or the owners of the AlphaDEX® Style Funds into consideration in determining, composing or calculating the Indices. The Corporations are not responsible for and have not participated in the determination of the timing of, prices at, or quantities of the AlphaDEX® Style Funds to be issued or in the determination or calculation of the equation by which an AlphaDEX® Style Fund is to be converted into cash. The Corporations have no liability in connection with the administration, marketing or trading of the AlphaDEX® Style Funds.

THE CORPORATIONS DO NOT GUARANTEE THE ACCURACY AND/OR UNINTERRUPTED CALCULATION OF THE INDICES OR ANY DATA INCLUDED THEREIN. THE CORPORATIONS MAKE NO WARRANTY, EXPRESS OR IMPLIED, AS TO RESULTS TO BE OBTAINED BY FIRST TRUST, OWNERS OF THE ALPHADEX® STYLE FUNDS, OR ANY OTHER PERSON OR ENTITY FROM THE USE OF THE INDICES OR ANY DATA INCLUDED THEREIN. THE CORPORATIONS MAKE NO EXPRESS OR IMPLIED WARRANTIES, AND EXPRESSLY DISCLAIM ALL WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR USE WITH RESPECT TO THE INDICES OR ANY DATA INCLUDED THEREIN. WITHOUT LIMITING ANY OF THE FOREGOING, IN NO EVENT SHALL THE CORPORATIONS HAVE ANY LIABILITY FOR ANY LOST PROFITS OR SPECIAL, INCIDENTAL, PUNITIVE, INDIRECT, OR CONSEQUENTIAL DAMAGES, EVEN IF NOTIFIED OF THE POSSIBILITY OF SUCH DAMAGES.

“AlphaDEX®” is a registered trademark of FTP. The Trust and First Trust, on behalf of the Funds, have been granted the right by FTP to use the name “AlphaDEX®” for certain purposes.

Exchanges. The only relationship that NYSE Arca has with First Trust or the Distributor of the Funds in connection with the Funds is that ICE Data Indices, LLC, an affiliate of NYSE Arca, is the Index Provider for the AlphaDEX® Sector Funds and NYSE Arca lists the shares of the Funds pursuant to its listing agreement with the Trust. NYSE Arca is not responsible for and has not participated in the determination of pricing or the timing of the issuance or sale of the shares of the Funds or in the determination or calculation of the asset value of the Funds. NYSE Arca has no obligation or liability in connection with the administration, marketing or trading of the Funds.

The only relationship that Nasdaq has with First Trust or the Distributor of the Funds in connection with the Funds is that Nasdaq is the Index Provider for the AlphaDEX® Style Funds and Nasdaq lists the shares of the Funds pursuant to its listing agreement with the Trust. Nasdaq is not responsible for and has not participated in the determination of pricing or the timing of the issuance or sale of the shares of the Funds or in the determination or calculation of the net asset value of the Funds. Nasdaq has no obligation or liability in connection with the administration, marketing or trading of the Funds.

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Additional Payments to Financial Intermediaries

First Trust or its affiliates may from time to time make payments, out of their own resources, to certain broker-dealers, registered investment advisers, banks or other intermediaries (collectively, “intermediaries”) that sell shares of First Trust mutual funds and ETFs (“First Trust Funds”) to promote the sales and retention of Fund shares by those firms and their customers. The amounts of these payments vary by intermediary. The level of payments that First Trust is willing to provide to a particular intermediary may be affected by, among other factors, (i) the firm’s total assets or Fund shares held in and recent net investments into First Trust Funds, (ii) the value of the assets invested in the First Trust Funds by the intermediary’s customers, (iii) redemption rates, (iv) its ability to attract and retain assets, (v) the intermediary’s reputation in the industry, (vi) the level and/or type of marketing assistance and educational activities provided by the intermediary, (vii) the firm’s level of participation in First Trust Funds’ sales and marketing programs, (viii) the firm’s compensation program for its registered representatives who sell Fund shares and provide services to Fund shareholders, and (ix) the asset class of the First Trust Funds for which these payments are provided. Such payments are generally asset-based but also may include the payment of a lump sum.

First Trust and/or its affiliates may make payments, out of its own assets, to those firms as compensation and/or reimbursement for marketing support and/or program servicing to selected intermediaries that are registered as holders or dealers of record for accounts invested in one or more of the First Trust Funds or that make First Trust Fund shares available through certain selected Fund no-transaction fee institutional platforms and fee-based wrap programs at certain financial intermediaries. Program servicing payments typically apply to employee benefit plans, such as retirement plans, or fee-based advisory programs but may apply to retail sales and assets in certain situations. The payments are based on such factors as the type and nature of services or support furnished by the intermediary and are generally asset-based. Services for which an intermediary receives marketing support payments may include, but are not limited to, business planning assistance, advertising, educating the intermediary’s personnel about First Trust Funds in connection with shareholder financial planning needs, placement on the intermediary’s preferred or recommended fund list, and access to sales meetings, sales representatives and management representatives of the intermediary. In addition, intermediaries may be compensated for enabling representatives of First Trust and/or its affiliates to participate in and/or present at conferences or seminars, sales or training programs for invited registered representatives and other employees, client and investor events and other events sponsored by the intermediary. Services for which an intermediary receives program servicing payments typically include, but are not limited to, record keeping, reporting or transaction processing and shareholder communications and other account administration services, but may also include services rendered in connection with Fund/investment selection and monitoring, employee enrollment and education, plan balance rollover or separation, or other similar services. An intermediary may perform program services itself or may arrange with a third party to perform program services. These payments, if any, are in addition to the service fee and any applicable omnibus sub-accounting fees paid to these firms with respect to these services by the First Trust Funds out of Fund assets.

From time to time, First Trust and/or its affiliates, at its expense, may provide other compensation to intermediaries that sell or arrange for the sale of shares of the First Trust Funds, which may be in addition to marketing support and program servicing payments described above. For example, First Trust and/or its affiliates may: (i) compensate intermediaries for National Securities Clearing Corporation networking system services (e.g., shareholder communication, account statements, trade confirmations and tax reporting) on an asset-based or per-account basis; (ii) compensate intermediaries for providing Fund shareholder trading information; (iii) make one-time or periodic payments to reimburse selected intermediaries for items such as ticket charges (i.e., fees that an intermediary charges its representatives for effecting transactions in Fund shares) or exchange order, operational charges (e.g., fees that an intermediary charges for establishing a Fund on its trading system), and literature printing and/or distribution costs; (iv) at the direction of a retirement plan’s sponsor, reimburse or pay direct expenses of an employee benefit plan that would otherwise be payable by the plan; (v) provide payments to broker-dealers to help defray their technology or infrastructure costs; and (vi) make payments for expenses associated with intermediaries’ use of First Trust Funds including, but not limited to, the use of First Trust Funds in model portfolios.

When not provided for in a marketing support or program servicing agreement, First Trust and/ or its affiliates may also pay intermediaries for enabling First Trust and/or its affiliates to participate in and/or present at conferences or seminars, sales or training programs for invited registered representatives and other intermediary employees, client and investor events and other intermediary-sponsored events, and for travel expenses, including lodging incurred by registered representatives and other employees in connection with prospecting, asset retention and due diligence trips. These payments may vary depending upon the nature of the event. First Trust and/or its affiliates make payments for such events as it deems appropriate, subject to its internal guidelines and applicable law.

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First Trust and/or its affiliates occasionally sponsor due diligence meetings for registered representatives during which they receive updates on various First Trust Funds and are afforded the opportunity to speak with portfolio managers. Although invitations to these meetings are not conditioned on selling a specific number of shares, those who have shown an interest in First Trust Funds are more likely to be considered. To the extent permitted by their firm’s policies and procedures, all or a portion of registered representatives’ expenses in attending these meetings may be covered by First Trust and/or its affiliates.

The amounts of payments referenced above made by First Trust and/or its affiliates could be significant and may create an incentive for an intermediary or its representatives to recommend or offer shares of the First Trust Funds to its customers. The intermediary may elevate the prominence or profile of the First Trust Funds within the intermediary’s organization by, for example, placing the First Trust Funds on a list of preferred or recommended funds and/or granting First Trust and/or its affiliates preferential or enhanced opportunities to promote the First Trust Funds in various ways within the intermediary’s organization. These payments are made pursuant to negotiated agreements with intermediaries. The payments do not change the price paid by investors for the purchase of a share or the amount a Fund will receive as proceeds from such sales. Furthermore, many of these payments are not reflected in the fees and expenses listed in the fee table section of a Fund's Prospectus because they are not paid by a Fund. The types of payments described herein are not mutually exclusive, and a single intermediary may receive some or all types of payments as described.

Other compensation may be offered to the extent not prohibited by state laws or any self-regulatory agency, such as FINRA. Investors can ask their intermediaries for information about any payments they receive from First Trust and/or its affiliates and the services it provides for those payments. Investors may wish to take intermediary payment arrangements into account when considering and evaluating any recommendations relating to Fund shares.

Payments to intermediaries, in certain circumstances, may also be made in connection with the distribution of model portfolios developed by First Trust, such as the inclusion of such model portfolios on an intermediary’s platform, as well as in connection with the marketing and sale of, and/or product training regarding such model portfolios, or servicing of accounts tracking such model portfolios. Such payments may be variable or fixed fee payments for platform support, or other payments in the form of a variable or fixed fee or a per position fee, or may relate to the amount of assets an intermediary’s clients have invested in the First Trust Funds in such models developed by First Trust, the management fee, the total expense ratio, or sales of the First Trust Funds in such models developed by First Trust. Some intermediaries also provide related data regarding transactions in specific model portfolios, First Trust Funds and investment strategies to First Trust in exchange for a fee.

First Trust and/or its affiliates may enter into arrangements with third parties, such as a software provider, whereby First Trust may license certain technology or other services from such entity in exchange for licensing or other fees which may be, in whole or in part, dependent on the value of First Trust mutual funds or ETFs held through such software or other service. Such third party may also offer price concessions to broker dealers, investment advisers or other financial intermediaries that license technology or other services that may be dependent, in whole or in part, on the value of First Trust mutual funds or ETFs held through such software or other service.

Additional Information

Book Entry Only System. The following information supplements and should be read in conjunction with the Prospectus.

DTC Acts as Securities Depository for Fund Shares. Shares of the Funds are represented by securities registered in the name of The Depository Trust Company (“DTC”) or its nominee, Cede & Co., and deposited with, or on behalf of, DTC.

DTC, a limited-purpose trust company, was created to hold securities of its participants (the “DTC Participants”) and to facilitate the clearance and settlement of securities transactions among the DTC Participants in such securities through electronic book-entry changes in accounts of the DTC Participants, thereby eliminating the need for physical movement of securities certificates. DTC Participants include securities brokers and dealers, banks, trust companies, clearing corporations and certain other organizations, some of whom (and/or their representatives) own DTC. More specifically, DTC is owned by a number of its DTC Participants and by the New York Stock Exchange and FINRA. Access to the DTC system is also available to others such as banks, brokers, dealers and trust companies that clear through or maintain a custodial relationship with a DTC Participant, either directly or indirectly (the “Indirect Participants”).

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Beneficial ownership of shares is limited to DTC Participants, Indirect Participants and persons holding interests through DTC Participants and Indirect Participants. Ownership of beneficial interests in shares (owners of such beneficial interests are referred to herein as “Beneficial Owners”) is shown on, and the transfer of ownership is effected only through, records maintained by DTC (with respect to DTC Participants) and on the records of DTC Participants (with respect to Indirect Participants and Beneficial Owners that are not DTC Participants). Beneficial Owners will receive from or through the DTC Participant a written confirmation relating to their purchase and sale of shares.

Conveyance of all notices, statements and other communications to Beneficial Owners is effected as follows. Pursuant to a letter agreement between DTC and the Trust, DTC is required to make available to the Trust upon request and for a fee to be charged to the Trust a listing of the shares of the Funds held by each DTC Participant. The Trust shall inquire of each such DTC Participant as to the number of Beneficial Owners holding shares, directly or indirectly, through such DTC Participant. The Trust shall provide each such DTC Participant with copies of such notice, statement or other communication, in such form, number and at such place as such DTC Participant may reasonably request, in order that such notice, statement or communication may be transmitted by such DTC Participant, directly or indirectly, to such Beneficial Owners. In addition, the Trust shall pay to each such DTC Participants a fair and reasonable amount as reimbursement for the expenses attendant to such transmittal, all subject to applicable statutory and regulatory requirements.

Fund distributions shall be made to DTC or its nominee, as the registered holder of all Fund shares. DTC or its nominee, upon receipt of any such distributions, shall immediately credit DTC Participants’ accounts with payments in amounts proportionate to their respective beneficial interests in shares of the Funds as shown on the records of DTC or its nominee. Payments by DTC Participants to Indirect Participants and Beneficial Owners of shares held through such DTC Participants will be governed by standing instructions and customary practices, as is now the case with securities held for the accounts of customers in bearer form or registered in a “street name,” and will be the responsibility of such DTC Participants.

The Trust has no responsibility or liability for any aspect of the records relating to or notices to Beneficial Owners, or payments made on account of beneficial ownership interests in such shares, or for maintaining, supervising or reviewing any records relating to such beneficial ownership interests, or for any other aspect of the relationship between DTC and the DTC Participants or the relationship between such DTC Participants and the Indirect Participants and Beneficial Owners owning through such DTC Participants.

DTC may decide to discontinue providing its service with respect to shares at any time by giving reasonable notice to the Trust and discharging its responsibilities with respect thereto under applicable law. Under such circumstances, the Trust shall take action to find a replacement for DTC to perform its functions at a comparable cost.

Policy Regarding Investment in Other Investment Companies. The Funds will not rely on Sections 12(d)(1)(F) or 12(d)(1)(G) of the 1940 Act to invest in other investment companies.

INFORMATION FOR INVESTORS IN THE EUROPEAN ECONOMIC AREA (“EEA”) ONLY

The following disclosures are included in this SAI solely for the purposes of compliance with the applicable EEA law and regulation resulting from, of and as a consequence of, the Funds’ registration or notification under the EU Directive on Alternative Investment Fund Managers (Directive (2011/61/EU)) (the “AIFM Directive”) national private placement regimes in certain European Union (“EU”) and EEA jurisdictions. The following disclosures are not intended for, and should not be relied on by, any investor other than an investor in the relevant EU and/or EEA jurisdictions because the rules, regulations and requirements applicable to the Funds in those jurisdictions as a result of their registration or notification differ from the rules, regulations and requirements applicable to the Funds under the Investment Company Act.

European Union’s Sustainable Finance Disclosure Regulation

While First Trust Advisors L.P. (the “Advisor”) is not itself generally subject to Regulation 2019/2088 of the European Parliament and of the Council on sustainability-related disclosures in the financial sector (“SFDR”), by virtue of the Funds’ registration or notification under the AIFM Directive national private placement regimes in certain EU and EEA jurisdictions, some limited disclosures under the SFDR must be made in respect of the Funds and the following section is intended to satisfy certain of such requirements. The SFDR requires the Advisor to determine, on a product-by-product basis, whether “sustainability risks” are relevant to the Advisor’s in-scope financial products, including the Funds.

For the purposes of SFDR, “sustainability risk” means an environmental, social or governance (“ESG”) event or condition that, if it occurs, could cause an actual or a potential material negative impact on the value of an investment.

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Solely for the purposes of SFDR, the Advisor has determined that sustainability risks are not relevant to the Funds on the basis that the Fund invests principally in investments or asset classes which, in the opinion of the Advisor, are not ordinarily subject to sustainability risk as a material negative impact on the value of those investments, as such terms are interpreted and applied under SFDR.

Consequently, the Advisor does not integrate sustainability risks into its investment decision making for the Funds and the Advisor has not assessed the likely impacts of sustainability risks on the returns of the Funds, as such terms are interpreted and applied under SFDR.

The Advisor will keep its assessment that sustainability risks are not relevant to the Funds under regular review.

SFDR requires the Advisor to disclose whether, and if so how, it considers the principal adverse impacts (“PAIs”) of its investment decisions on sustainability factors, in accordance with a specific regime outlined in SFDR, in relation to the Funds. The Advisor does not consider the principal adverse impacts of its investment decisions on sustainability factors (either generally or in relation to the Funds).

In addition, the Advisor considers that its primary investment strategies and client relationships do not support adoption of the PAI regime within SFDR.

Information for Investors in the EEA Regarding Offering of the Funds

In relation to each Member State of the EEA which has implemented the AIFM Directive, the Prospectus, and any summary Prospectus or SAI relating to the Funds, may only be distributed and shares may only be offered or placed in a Member State to the extent that: (1) the Funds are permitted to be marketed to professional investors in the relevant member state in accordance with the AIFM Directive (as implemented into the local law/regulations of the relevant Member State); or otherwise (2) the Prospectus and SAI may be lawfully distributed and the shares may lawfully be offered or placed in that Member State (including at the initiative of the investor).

In relation to each Member State of the EEA which, at the date of this SAI, has not implemented the AIFM Directive, the Prospectus and this SAI may only be distributed and shares may only be offered or placed to the extent that the Prospectus and this SAI may be lawfully distributed and the shares may lawfully be offered or placed in that Member State (including at the initiative of the investor).

In addition, the following restrictions apply to the distribution of the Prospectus and SAI in the following Member States:

Information for Investors in the United Kingdom

Subject always to the foregoing notice in respect of the EEA, this SAI is being issued in the United Kingdom by First Trust Global Portfolios Limited (which is authorized and regulated by the Financial Conduct Authority (the “FCA”)) only to and/or is directed only at persons who are professional clients or eligible counterparties for the purposes of the FCA’s Conduct of Business Sourcebook. The opportunity to invest in the Funds is only available to such persons in the United Kingdom, and the Prospectus and SAI must not be relied on or acted upon by any other persons in the United Kingdom.

Information for Investors in Ireland

The distribution of this Prospectus and SAI in Ireland and the offering or purchase of shares is restricted to the individual to whom it is addressed. Accordingly, it may not be reproduced in whole or in part, nor may its contents be distributed in writing or orally to any third party and it may be read solely by the person to whom it is addressed and his/her professional advisers. Shares in the Funds will not be offered or sold by any person:

(a)

otherwise than in conformity with the provisions of the European Communities (Markets in Financial Instruments) Regulations 2007 and the European Union (Alternative Investment Fund Managers) Regulations 2013, each as amended; or

(b)

in any way which would require the publication of a prospectus under the Companies Act 2014 or any regulations made thereunder; or

(c)

in Ireland except in all circumstances that will result in compliance with all applicable laws and regulations in Ireland.

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AIFM Directive Disclosures

Background. The AIFM Directive is an EU directive which regulates the management and marketing of funds within the EEA. The AIFM Directive distinguishes between EU and non-EU funds and EU and non-EU fund managers and different obligations apply under the AIFM Directive depending on where the fund is based and where the manager is based. Certain disclosure, transparency and reporting obligations are imposed on non-EU fund managers wishing to market funds to investors in the EEA. There are additional requirements imposed on EU fund managers, which do not currently apply to First Trust.

To the extent not already disclosed to you prior to your investment in the Funds, the purpose of this section of this SAI is to satisfy the disclosures which are required to be provided to you under the AIFM Directive.

Overview of the Funds and the Service Providers. The Funds are non-EU AIFs (“AIF” means an alternative investment fund for the purposes of the AIFM Directive).

First Trust Advisors L.P. (“First Trust”) is the AIFM of the Funds (“AIFM” means an alternative investment fund manager for the purposes of the AIFM Directive). First Trust is a non-EU AIFM.

The Trust has entered into agreements with various service providers including First Trust (as the Investment Advisor), the Custodian, Distributor, Transfer Agent, Administrator, index providers and the exchange where each Fund is listed in respect of the Funds. Further details regarding the duties and roles of such service providers can be found in the Prospectus and this SAI for the Funds.

In addition to the parties listed above, the Trust has appointed (i) Chapman and Cutler LLP as its legal counsel which advises it on US legal matters; (ii) Deloitte & Touche LLP as the Funds’ auditors who undertake to audit the Funds’ financial statements in accordance with the standards of the Public Company Accounting Oversight Board (PCAOB) (United States); and (iii) CT Corporation System as the Funds’ registered agent.

First Trust is not required to ensure that the Funds appoint, and the Funds have not appointed, a depositary for purposes of the AIFM Directive (a depositary in the context of the AIFM Directive, has a specific role and function. The appointment of such depositary is not required for non-EU AIFs with non-EU AIFMs). As such investors in the Funds have no rights as against any person in respect of the duties or liabilities of a depositary under the AIFM Directive.

Investors’ Contractual Rights. In respect of each of the service providers to the Funds, investors who purchase shares in the Funds in the secondary market have no direct rights of action against the service providers, as a matter of contract law or under the establishment documents of the Trust. The proper plaintiff in an action in respect of which a wrongdoing is alleged to have been committed against the Funds or the Trust by a service provider is, prima facie, the Trust itself. An investor may bring a derivative or similar action or proceeding (“Derivative Action”) against the Trust or a Fund to recover a judgment in its favor in accordance with the provisions of the Declaration. Accordingly, investors would have no direct contractual right against the relevant service provider for breach of the agreement governing its appointment by the Trust. The foregoing disclosure is without prejudice to such other rights of action (for example, under the securities laws, tort law or in respect of breach of fiduciary duty) which might in certain situations be separately available to investors.

Investment in the Funds. Investors will buy shares in the Funds in secondary market transactions through brokers and will not subscribe for shares from the Trust directly. As such, there is no direct contractual relationship between the Funds and the investor in connection with the purchase or sale of shares. While the Funds are established under Massachusetts law and Massachusetts law does facilitate the enforcement of judgments obtained in foreign jurisdictions, investors who buy shares on the secondary market will have no direct contractual right of action against the Funds. Investors should refer to “How to Buy and Sell Shares” in the main body of the Prospectus for more detail. The foregoing disclosure is without prejudice to such other rights of action (for example, under the securities laws, tort law or in respect of breach of fiduciary duty) which might in certain situations be separately available to investors.

Redemption from the Funds. Non-US investors will sell shares in secondary market transactions through brokers and will not redeem shares from the Funds directly. Shares can be sold throughout the trading day like other publically traded shares. Investors should refer to “How to Buy and Sell Shares” in the main body of the Prospectus for more detail.

Liquidity Risk Management. Investors should note that while First Trust is not required to implement liquidity management arrangements in accordance with the AIFM Directive in respect of the Funds, the Funds are subject to the liquidity limitations established by the SEC. The Trustees have delegated to First Trust the day-to-day determination of illiquidity of equity and fixed income securities as described under “Illiquid Securities” in this SAI.

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Treatment of Investors. The Trust and the AIFM do not offer any investors preferential treatment or the right to obtain preferential treatment. Whilst the Trust does not take specific steps to ensure the fair treatment of investors, under the 1940 Act the Trustees are required to monitor how a Fund operates and oversee matters where the interests of the Fund and its shareholders may differ from those of its investment adviser.

First Trust is registered as an investment adviser with the SEC, and is subject to regulation and oversight designed to protect shareholders. Under the Investment Advisers Act of 1940, First Trust is a fiduciary to its clients, including the Funds, and is therefore required to act in the best interests of clients and to place the interests of clients before its own.

Information Regarding the use of Leverage and Collateral. The AIFM Directive requires disclosure of certain information relating to leverage, collateral and asset re-use arrangements. The Funds may obtain leverage through the use of derivatives and other non-fully funded investments such as reverse repurchase agreements, firm commitment agreements and standby commitment agreements if, and to the extent that, such transactions are (i) disclosed in the Funds’ Prospectus and SAI and (ii) deemed appropriate investments by First Trust. These leveraged trading practices generally have not been prohibited by the SEC, though the SEC has published guidance on the manner in which the Funds may cover their leveraged trading practices to limit leverage and avoid the need to address the leverage concerns in Section 18 of the 1940 Act, which severely restricts how the Funds may use leverage. All arrangements entered into by First Trust on behalf of the Funds which result in leverage follow the parameter of the guidance published by the SEC.

As a non-EU AIFM, First Trust is not obliged to set a maximum permitted level of leverage which it may employ in its management of the Funds. The total amount of leverage employed by the Funds is provided at http://www.ftglobalportfolios.com.

Investors should refer to the “Investment Objectives and Policies” and “Investment Strategies” section of this SAI for more details on the use and risk of leverage by the Funds.

Shareholder Voting Rights. The Declaration requires a shareholder vote only on those matters where the 1940 Act requires a vote of shareholders and otherwise permits the Trustees to take actions without seeking the consent of shareholders. The Funds’ fundamental policies, as described in the “Investment Objectives and Policies” section of this SAI, may not be changed without approval of the holders of a majority of the outstanding voting securities (as such term is defined in the 1940 Act) of a Fund. The 1940 Act defines a majority vote as the vote of the lesser of (i) 67% or more of the voting securities represented at a meeting at which more than 50% of the outstanding securities are represented; or (ii) more than 50% of the outstanding voting securities.

Net Asset Value. The latest NAV of the Funds, and the latest NAV per share of each class of share of the Funds, is available online at: http://www.ftglobalportfolios.com and online stock quote services. Generally investors will buy and sell shares of the Funds in secondary market transactions through brokers. Shares of the Funds will therefore be available at the relevant market price rather than NAV.

The historical performance of the Funds since inception is available online at: http://www.ftglobalportfolios.com.

Accounts. Under the AIFM Directive, First Trust is required to make available the annual report of the Funds that it markets in the EEA. This must be prepared by no later than 6 months following the end of the financial year and contain certain specific content requirements set out in the AIFM Directive. Once the annual report has been produced, it will be made available to investors in the manner as set out in the Prospectus.

Professional Liability Requirements/Delegation by the AIFM/Valuation. As a non-EU AIFM, First Trust is not subject to certain EU requirements relating to (i) the cover of professional liability risk by holding either additional of its own funds or appropriate professional liability insurance; (ii) permitted delegation and the management and disclosure of conflicts of interest relating to any such delegation; and (iii) valuation as set out in Article 19 of the AIFM Directive. As such, no disclosures for the purposes of the AIFM Directive have been made. Notwithstanding this, First Trust and the Funds continue to comply with their requirements under US law.

Periodic Disclosure Obligations. The following information will be disclosed to Fund shareholders on a periodic basis by way of a posting being made on http://www.ftglobalportfolios.com:

●

the percentage of the Funds’ assets, if any, that are subject to special arrangements arising from their illiquid nature (including, but not limited to, deferrals of redemptions and suspensions);

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●

the current risk profile of each Fund and the risk management systems employed by the AIFM to manage those risks; and

●

the total amount of leverage employed by each Fund, if any.

Whenever any new arrangements for managing the liquidity of the Funds are introduced including, but not limited to, any material changes to the liquidity management systems and procedures employed by First Trust, a disclosure to this effect will be uploaded on the Funds’ website. The Fund swill ensure that a notice is uploaded on an expedited basis whenever deferrals or other similar special arrangements are activated or where redemptions of shares are suspended.

A notice will be posted without undue delay whenever there is a change to a maximum level of leverage which may be employed on behalf of a Fund; and any changes are made to the right of re-use of collateral or any changes to any guarantee granted under any leveraging arrangement.

INFORMATION FOR INVESTORS IN HONG KONG ONLY

The Fund is a collective investment scheme but is not authorized under Section 104 of the Securities and Futures Ordinance of Hong Kong by the Securities and Futures Commission of Hong Kong. Accordingly, the distribution of the Prospectus, and the placement of Fund shares in Hong Kong, is restricted. The Prospectus may only be distributed, circulated or issued to persons who are professional investors under the Securities and Futures Ordinance and any rules made under that Ordinance or as otherwise permitted by the Securities and Futures Ordinance.

INFORMATION FOR INVESTORS IN SINGAPORE ONLY

The Prospectus has not been registered as a Prospectus with the Monetary Authority of Singapore. Accordingly, the Prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of Fund shares may not be circulated or distributed, nor may Fund shares be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor pursuant to Section 304 of the Securities and Futures Act, Chapter 289 of Singapore (the “SFA”)) or (ii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

INFORMATION FOR INVESTORS IN TAIWAN ONLY

Fund shares are being made available in the Republic of China (“R.O.C.”) on a private placement basis only to banks, bills houses, trust enterprises, financial holding companies and other qualified entities or institutions (collectively, “Qualified Institutions”) and other entities and individuals meeting specific criteria (“Other Qualified Investors”) pursuant to the private placement provisions of the R.O.C. Rules Governing Offshore Funds. No other offer or sale of the shares of the Fund in the R.O.C. is permitted. R.O.C. purchasers of Fund shares may not sell or otherwise dispose of their holdings except by redemption, transfer to a Qualified Institution or Other Qualified Investor, transfer by operation of law or other means approved by the R.O.C. Financial Supervisory Commission.

Proxy Voting Policies and Procedures

The Trust has adopted a proxy voting policy that seeks to ensure that proxies for securities held by the Funds are voted consistently with the best interests of the Funds.

The Board has delegated to First Trust the proxy voting responsibilities for the Funds and has directed First Trust to vote proxies consistent with the Funds' best interests. The First Trust Proxy Voting Policies and Procedures are attached hereto as Exhibit B. First Trust has engaged the services of Institutional Shareholder Services Inc. (“ISS”) to make recommendations to First Trust on the voting of proxies relating to securities held by the Funds. If First Trust manages the assets of a company or its pension plan and any of First Trust’s clients hold any securities of that company, First Trust will generally vote proxies relating to such company’s securities in accordance with the ISS recommendations to avoid any conflict of interest.

First Trust has adopted the ISS Proxy Voting Guidelines. While these guidelines are not intended to be all-inclusive, they do provide guidance on First Trust’s general voting policies. First Trust’s use of the ISS Proxy Voting Guidelines is not intended to constrain First Trust’s consideration of any proxy proposal, and there are times when First Trust deviates from the ISS Proxy Voting Guidelines. This includes when required by Rule 12d1-4 under the 1940 Act or when agreed to by the

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Fund and certain acquired funds as permitted under Rule 12d1-4 under the 1940 Act, if applicable. Generally, First Trust will not rely on ISS Proxy Voting Guidelines to withhold votes or vote against directors solely based on quota criteria or the exclusion of certain climate-related disclosures, which may or may not relate to the company’s core business or may not materially impact shareholder value. First Trust will consider such proxy voting decisions in light of merit-based considerations which it believes may impact shareholder value. First Trust retains final authority and fiduciary responsibility for proxy voting.

Information regarding how the Funds voted proxies (if any) relating to portfolio securities during the most recent 12-month period ended June 30 is available upon request and without charge on the Funds' website at http://www.ftportfolios.com, by calling (800) 621-1675 or by accessing the SEC’s website at http://www.sec.gov.

Portfolio Schedule. Each Fund files portfolio holdings information for each month in a fiscal quarter within 60 days after the end of the relevant fiscal quarter on Form N-PORT. Portfolio holdings information for the third month of each fiscal quarter will be publicly available on the SEC’s website at http://www.sec.gov. Each Fund’s complete schedule of portfolio holdings for the second and fourth quarters of each fiscal year is included in the semi-annual and annual reports to shareholders, respectively, and is filed with the SEC on Form N-CSR. A semi-annual or annual report for each Fund will become available to investors within 60 days after the period to which it relates. Each Fund’s Forms N-PORT and Forms N-CSR are available on the SEC’s website listed above.

Policy Regarding Disclosure of Portfolio Holdings. The Trust has adopted a policy regarding the disclosure of information about each Fund’s portfolio holdings. The Board of Trustees must approve all material amendments to this policy. Each Fund’s portfolio holdings are publicly disseminated each day the Fund is open for business through financial reporting and news services, including publicly accessible Internet websites. In addition, a basket composition file, which includes the security names and share quantities to deliver in exchange for Fund shares, together with estimates and actual cash components, is publicly disseminated each day the NYSE is open for trading via the National Securities Clearing Corporation (“NSCC”). Pursuant to Rule 6c-11 under the 1940 Act, information regarding each Fund’s current portfolio holdings will be available on a daily basis at http://www.ftportfolios.com/Retail/etf/home.aspx. The Trust, First Trust, FTP and BNY will not disseminate non-public information concerning the Trust.

Codes of Ethics. In order to mitigate the possibility that the Funds will be adversely affected by personal trading, the Trust, First Trust and the Distributor have adopted Codes of Ethics under Rule 17j-1 of the 1940 Act. These Codes of Ethics contain policies restricting securities trading in personal accounts of the officers, Trustees and others who normally come into possession of information on portfolio transactions. Personnel subject to the Codes of Ethics may invest in securities that may be purchased or held by the Funds; however, the Codes of Ethics require that each transaction in such securities be reviewed by the Chief Compliance Officer or his or her designee. These Codes of Ethics are on public file with, and are available from, the SEC.

Creation and Redemption of Creation Units

General.  ETFs, such as the Funds, generally issue and redeem their shares in primary market transactions through a creation and redemption mechanism and do not sell or redeem individual shares. Instead, financial entities known as “Authorized Participants” have contractual arrangements with an ETF or one of the ETF’s service providers to purchase and redeem ETF shares directly with the ETF in large blocks of shares known as “Creation Units.” Prior to the start of trading on every business day, an ETF publishes through the National Securities Clearing Corporation (“NSCC”) the “basket” of securities, cash or other assets that it will accept in exchange for a Creation Unit of the ETF’s shares. An Authorized Participant that wishes to effectuate a creation of an ETF’s shares deposits with the ETF the “basket” of securities, cash or other assets identified by the ETF that day, and then receives the Creation Unit of the ETF’s shares in return for those assets. After purchasing a Creation Unit, the Authorized Participant may continue to hold the ETF’s shares or sell them in the secondary market. The redemption process is the reverse of the purchase process: the authorized participant redeems a Creation Unit of ETF shares for a basket of securities, cash or other assets. The combination of the creation and redemption process with secondary market trading in ETF shares and underlying securities provides arbitrage opportunities that are designed to help keep the market price of ETF shares at or close to the NAV per share of the ETF.

Authorized Participants.  An “Authorized Participant” is a member or participant of a clearing agency registered with the SEC that has a written agreement with a Fund or one of its service providers that allows the Authorized Participant to place orders for the purchase or redemption of Creation Units (a “Participant Agreement”). Orders to purchase Creation Units must be delivered through an Authorized Participant that has executed a Participant Agreement and must comply with

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the applicable provisions of such Participant Agreement. Investors wishing to purchase or sell shares generally do so on an exchange. Institutional investors other than Authorized Participants are responsible for making arrangements for a redemption request to be made through an Authorized Participant.

Business Day.  A “Business Day” is generally any day on which the New York Stock Exchange (“NYSE”), the Exchange and the Trust are open for business. As of the date of this SAI, the NYSE observes the following holidays: New Year’s Day, Martin Luther King, Jr. Day, Presidents’ Day, Good Friday, Memorial Day, Juneteenth, Independence Day, Labor Day, Thanksgiving Day and Christmas Day. The Business Day on which an order to purchase or redeem Creation Units is received in proper form is referred to as the “Transmittal Date.”

Basket Composition.  Rule 6c-11(c)(3) under of the 1940 Act requires an ETF relying on the exemptions offered by Rule 6c-11 to adopt and implement written policies and procedures governing the construction of baskets and the process that the ETF will use for the acceptance of baskets. In general, in connection with the construction and acceptance of baskets, the Advisor may consider various factors, including, but not limited to: (1) whether the securities, assets and other positions comprising a basket are consistent with the ETF’s investment objective(s), policies and disclosure; (2) whether the securities, assets and other positions can legally and readily be acquired, transferred and held by the ETF and/or Authorized Participant(s), as applicable; (3) whether to utilize cash, either in lieu of securities or other instruments or as a cash balancing amount; and (4) in the case of an ETF that tracks an index, whether the securities, assets and other positions aid index tracking.

Each Fund may utilize a pro rata basket or a custom basket in reliance on Rule 6c-11. A “pro rata basket” is a basket that is a pro rata representation of the ETF’s portfolio holdings, except for minor deviations when it is not operationally feasible to include a particular instrument within the basket, except to the extent that the Fund utilized different baskets in transactions on the same Business Day.

Rule 6c-11 defines “custom baskets” to include two categories of baskets. First, a basket containing a non-representative selection of the ETF’s portfolio holdings would constitute a custom basket. These types of custom baskets include, but are not limited to, baskets that do not reflect: (i) a pro rata representation of the Fund’s portfolio holdings; (ii) a representative sampling of an ETF’s portfolio holdings; or (iii) changes due to a rebalancing or reconstitution of an ETF’s securities market index, if applicable. Second, if different baskets are used in transactions on the same Business Day, each basket after the initial basket would constitute a custom basket. For example, if an ETF exchanges a basket with either the same or another Authorized Participant that reflects a representative sampling that differs from the initial basket, that basket (and any such subsequent baskets) would be a custom basket. Similarly, if an ETF substitutes cash in lieu of a portion of basket assets for a single Authorized Participant, that basket would be a custom basket. The Advisor’s Rule 6c-11 Committee defines any deviation from a pro rata basket to be a “custom basket.” Rebalancing and reconstitution baskets do not constitute custom baskets. All cash baskets that are the initial basket on a Business Day also do not constitute custom baskets.

Under a variety of circumstances, an ETF and its shareholders may benefit from the flexibility afforded by custom baskets. In general terms, the use of custom baskets may reduce costs, increase efficiency and improve trading. Because utilizing custom baskets provides a way for an ETF to add, remove and re-weight portfolio securities without transacting in the market, it may help the ETF to avoid transaction costs and adverse tax consequences. Rule 6c-11 provides an ETF with flexibility to use “custom baskets” if the ETF has adopted written policies and procedures that: (1) set forth detailed parameters for the construction and acceptance of custom baskets that are in the best interests of the ETF and its shareholders, including the process for any revisions to, or deviations from, those parameters; and (2) specify the titles or roles of employees of the ETF’s investment advisor who are required to review each custom basket for compliance with those parameters.

The use of baskets that do not correspond pro rata to an ETF’s portfolio holdings has historically created concern that an Authorized Participant could take advantage of its relationship with an ETF and pressure the ETF to construct a basket that favors an Authorized Participant to the detriment of the ETF’s shareholders. For example, because ETFs rely on Authorized Participants to maintain the secondary market by promoting an effective arbitrage mechanism, an Authorized Participant holding less liquid or less desirable securities potentially could pressure an ETF into accepting those securities in its basket in exchange for liquid ETF shares (i.e., dumping). An Authorized Participant also could pressure the ETF into including in its basket certain desirable securities in exchange for ETF shares tendered for redemption (i.e., cherry-picking). In either case, the ETF’s other investors would be disadvantaged and would be left holding shares of an ETF with a less liquid or less desirable portfolio of securities. The Advisor has adopted policies and procedures designed to mitigate these concerns but there is ultimately no guarantee that such policies and procedures will be effective.

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Basket Dissemination.  Basket files are published for consumption through the NSCC, a subsidiary of Depository Trust & Clearing Corporation, and can be utilized for pricing, creations, redemptions, rebalancing and custom scenarios. In most instances, pro rata baskets are calculated and supplied by the ETF’s custodial bank based on ETF holdings, whereas non-pro rata, custom and forward-looking pro rata baskets are calculated by the Fund’s investment advisor and disseminated by the ETF’s custodial bank through the NSCC process.

Placement of Creation or Redemption Orders.  All orders to purchase or redeem Creation Units are to be governed according to the applicable Participant Agreement that each Authorized Participant has executed. In general, all orders to purchase or redeem Creation Units must be received by the transfer agent in the proper form required by the Participant Agreement no later than the closing time of the regular trading session of the NYSE (ordinarily 4:00 p.m. Eastern Standard Time) on each day the NYSE is open for business (the “Closing Time”) in order for the purchase or redemption of Creation Units to be effected based on the NAV of shares of a Fund as next determined on such date after receipt of the order in proper form. However, at its discretion, the Fund may require an Authorized Participant to submit orders to purchase or redeem Creation Units be placed earlier in the day (such as instances where an applicable market for a security comprising a creation or redemption basket closes earlier than usual).

Delivery of Redemption Proceeds.  Deliveries of securities to Authorized Participants in connection with redemption orders are generally expected to be made within one Business Day. Due to the schedule of holidays in certain countries, however, the delivery of in-kind redemption proceeds for a Fund may take longer than one Business Day after the day on which the redemption request is received in proper form. Section 22(e) of the 1940 Act generally prohibits a registered open-end management investment company from postponing the date of satisfaction of redemption requests for more than seven days after the tender of a security for redemption. This prohibition can cause operational difficulties for ETFs that hold foreign investments and exchange in-kind baskets for Creation Units. For example, local market delivery cycles for transferring foreign investments to redeeming investors, together with local market holiday schedules, can sometimes require a delivery process in excess of seven days. However, Rule 6c-11 grants relief from Section 22(e) to permit an ETF to delay satisfaction of a redemption request for more than seven days if a local market holiday, or series of consecutive holidays, or the extended delivery cycles for transferring foreign investments to redeeming Authorized Participants, or the combination thereof prevents timely delivery of the foreign investment included in the ETF’s basket. Under this exemption, an ETF must deliver foreign investments as soon as practicable, but in no event later than 15 days after the tender to the ETF. The exemption therefore will permit a delay only to the extent that additional time for settlement is actually required, when a local market holiday, or series of consecutive holidays, or the extended delivery cycles for transferring foreign investments to redeeming authorized participants prevents timely delivery of the foreign investment included in the ETF’s basket. If a foreign investment settles in less than 15 days, Rule 6c-11 requires an ETF to deliver it pursuant to the standard settlement time of the local market where the investment trades. Rule 6c-11 defines “foreign investment” as any security, asset or other position of the ETF issued by a foreign issuer (as defined by Rule 3b-4 under the 1934 Act), and that is traded on a trading market outside of the United States. This definition is not limited to “foreign securities,” but also includes other investments that may not be considered securities. Although these other investments may not be securities, they may present the same challenges for timely settlement as foreign securities if they are transferred in kind.

Creation Transaction Fees.  Each Fund imposes fees in connection with the purchase of Creation Units. These fees may vary based upon various facts-based circumstances, including, but not limited to, the composition of the securities included in the Creation Unit or the countries in which the transactions are settled. The price for each Creation Unit will equal the daily NAV per share of a Fund times the number of shares in a Creation Unit, plus the fees described above and, if applicable, any operational processing and brokerage costs, transfer fees, stamp taxes and part or all of the spread between the expected bid and offer side of the market related to the securities comprising the creation basket.

Redemption Transaction Fees.  Each Fund also imposes fees in connection with the redemption of Creation Units. These fees may vary based upon various facts-based circumstances, including, but not limited to, the composition of the securities included in the Creation Unit or the countries in which the transactions are settled. The price received for each Creation Unit will equal the daily NAV per share of a Fund times the number of shares in a Creation Unit, minus the fees described above and, if applicable, any operational processing and brokerage costs, transfer fees, stamp taxes and part or all of the spread between the expected bid and offer side of the market related to the securities comprising the redemption basket. Investors who use the services of a broker or other such intermediary in addition to an Authorized Participant to effect a redemption of a Creation Unit may also be assessed an amount to cover the cost of such services. The redemption fee charged by a Fund will comply with Rule 22c-2 of the 1940 Act which limits redemption fees to no more than 2% of the value of the shares redeemed.

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Suspension of Creations.  The SEC has stated its position that an ETF generally may reject or suspend the issuance of Creation Units only for a limited time and only due to extraordinary circumstances, such as when the markets on which the ETF’s portfolio holdings are traded are closed for a limited period of time. The SEC has also stated that an ETF could not set transaction fees so high as to effectively suspend the issuance of Creation Units. Circumstances in which a Fund may suspend or reject creations include, but are not limited to: (i) the order is not in proper form; (ii) the purchaser or group of related purchasers, upon obtaining the Creation Units of Fund shares ordered, would own 80% or more of the currently outstanding shares of a Fund; (iii) the required consideration is not delivered; (iv) the acceptance of the basket would, in the opinion of a Fund, be unlawful; or (v) there exist circumstances outside the control of a Fund that make it impossible to process purchases of Creation Units for all practical purposes. Examples of such circumstances include: acts of God or public service or utility problems such as fires, floods, extreme weather conditions and power outages resulting in telephone, telecopy and computer failures; market conditions or activities causing trading halts; systems failures involving computer or other information systems affecting a Fund, First Trust, the Distributor, DTC, NSCC, the transfer agent, the custodian, any sub-custodian or any other participant in the purchase process; and similar extraordinary events. Each Fund reserves the right to reject a creation order transmitted to it provided that such action does not result in a suspension of sales of creation units in contravention of 6c-11 and the SEC’s positions thereunder. The Transfer Agent shall notify a prospective creator of a Creation Unit and/or the Authorized Participant acting on behalf of such prospective creator of the rejection of the order of such person. The Trust, a Fund, the Transfer Agent, the custodian, any sub-custodian and the Distributor are under no duty, however, to give notification of any defects or irregularities in the delivery of baskets, nor shall any of them incur any liability for the failure to give any such notification.

Suspension of Redemptions.  An ETF may suspend the redemption of Creation Units only in accordance with Section 22(e) of the 1940 Act. Section 22(e) stipulates that no registered investment company shall suspend the right of redemption, or postpone the date of payment or satisfaction upon redemption of any redeemable security in accordance with its terms for more than seven days after the tender of such security to the company or its agent designated for that purpose for redemption, except (1) for any period (A) during which the NYSE is closed other than customary week-end and holiday closings or (B) during which trading on the NYSE is restricted; (2) for any period during which an emergency exists as a result of which (A) disposal by the investment company of securities owned by it is not reasonably practicable or (B) it is not reasonably practicable for such company fairly to determine the value of its net assets; or (3) for such other periods as the SEC may by order permit for the protection of security holders of the investment company.

Exceptions to Use of Creation Units.  Under Rule 6c-11 of the 1940 Act, ETFs are permitted to sell or redeem individual shares on the day of consummation of a reorganization, merger, conversion, or liquidation. In these limited circumstances, an ETF may need to issue or redeem individual shares and may need to transact without utilizing Authorized Participants.

Federal Tax Matters

This section summarizes some of the main U.S. federal income tax consequences of owning shares of a Fund. This section is current as of the date of the SAI. Tax laws and interpretations change frequently, and these summaries do not describe all of the tax consequences to all taxpayers. For example, these summaries generally do not describe your situation if you are a corporation, a non-U.S. person, a broker-dealer or other investor with special circumstances. In addition, this section does not describe your state, local or foreign tax consequences.

This federal income tax summary is based in part on the advice of counsel to the Funds. The Internal Revenue Service (“IRS”) could disagree with any conclusions set forth in this section. The following disclosure may not be sufficient for prospective investors to use for the purpose of avoiding penalties under federal tax law.

As with any investment, prospective investors should seek advice based on their individual circumstances from their own tax advisor.

Each Fund intends to qualify annually and to elect to be treated as a regulated investment company (a “RIC”) under the Internal Revenue Code of 1986, as amended (the “Code”).

To qualify for the favorable U.S. federal income tax treatment generally accorded to RICs, a Fund must, among other things, (i) derive in each taxable year at least 90% of its gross income from dividends, interest, payments with respect to securities loans and gains from the sale or other disposition of stock, securities or foreign currencies or other income derived with respect to its business of investing in such stock, securities or currencies, or net income derived from interests in certain publicly traded partnerships; (ii) diversify its holdings so that, at the end of each quarter of the taxable year, (a) at least 50%

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of the market value of a Fund's assets is represented by cash and cash items (including receivables), U.S. government securities, the securities of other RICs and other securities, with such other securities of any one issuer generally limited for the purposes of this calculation to an amount not greater than 5% of the value of a Fund's total assets and not greater than 10% of the outstanding voting securities of such issuer, and (b) not more than 25% of the value of its total assets is invested in the securities (other than U.S. government securities or the securities of other RICs) of any one issuer, or two or more issuers which a Fund controls which are engaged in the same, similar or related trades or businesses, or the securities of one or more of certain publicly traded partnerships; and (iii) distribute at least 90% of its investment company taxable income (which includes, among other items, dividends, interest and net short-term capital gains in excess of net long-term capital losses) and at least 90% of its net tax-exempt interest income each taxable year. There are certain exceptions for failure to qualify if the failure is for reasonable cause or is de minimis, and certain corrective action is taken and certain tax payments are made by a Fund.

As a RIC, a Fund generally will not be subject to U.S. federal income tax on its investment company taxable income (as that term is defined in the Code, but without regard to the deduction for dividends paid) and net capital gain (the excess of net long-term capital gain over net short-term capital loss), if any, that it distributes to shareholders. Each Fund intends to distribute to its shareholders, at least annually, substantially all of its investment company taxable income and net capital gain. If a Fund retains any net capital gain or investment company taxable income, it will generally be subject to federal income tax at regular corporate rates on the amount retained. In addition, amounts not distributed on a timely basis in accordance with a calendar year distribution requirement are subject to a nondeductible 4% excise tax unless, generally, a Fund distributes during each calendar year an amount equal to the sum of (1) at least 98% of its ordinary income (not taking into account any capital gains or losses) for the calendar year, (2) at least 98.2% of its capital gains in excess of its capital losses (adjusted for certain ordinary losses) for the one-year period ending October 31 of the calendar year, and (3) any ordinary income and capital gains for previous years that were not distributed during those years. In order to prevent application of the excise tax, each Fund intends to make its distributions in accordance with the calendar year distribution requirement. A distribution will be treated as paid on December 31 of the current calendar year if it is declared by a Fund in October, November or December with a record date in such a month and paid by the Fund during January of the following calendar year. Such distributions will be taxable to shareholders in the calendar year in which the distributions are declared, rather than the calendar year in which the distributions are received.

Subject to certain reasonable cause and de minimis exceptions, if a Fund fails to qualify as a RIC or fails to satisfy the 90% distribution requirement in any taxable year, the Fund would be taxed as an ordinary corporation on its taxable income (even if such income were distributed to its shareholders) and all distributions out of earnings and profits would be taxed to shareholders as ordinary income.

Distributions

Dividends paid out of a Fund's investment company taxable income are generally taxable to a shareholder as ordinary income to the extent of the Fund’s earnings and profits, whether paid in cash or reinvested in additional shares. However, certain ordinary income distributions received from a Fund may be taxed at capital gains tax rates. In particular, ordinary income dividends received by an individual shareholder from RICs such as each of the Funds are generally taxed at the same rates that apply to net capital gain, provided that certain holding period requirements are satisfied and provided the dividends are attributable to qualifying dividends received by a Fund itself. Dividends received by a Fund from REITs and foreign corporations are qualifying dividends eligible for this lower tax rate only in certain circumstances.  A Fund will provide notice to its shareholders of the amount of any distributions that may be taken into account as a dividend which is eligible for the capital gains tax rates. A Fund cannot make any guarantees as to the amount of any distribution which will be regarded as a qualifying dividend. Some portion of the ordinary income distributions that are attributable to dividends received by a Fund from shares in certain real estate investment trusts may be designated by the Fund as eligible for a deduction for qualified business income, provided certain holding period requirements are satisfied.

Income from a Fund may also be subject to a 3.8% “Medicare tax.” This tax generally applies to net investment income if the taxpayer’s adjusted gross income exceeds certain threshold amounts, which are $250,000 in the case of married couples filing joint returns and $200,000 in the case of single individuals.

A corporation that owns shares generally will not be entitled to the dividends received deduction with respect to many dividends received from a Fund because the dividends received deduction is generally not available for distributions

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from RICs. However, certain ordinary income dividends on shares that are attributable to qualifying dividends received by the Funds from certain domestic corporations may be reported by a Fund as being eligible for the dividends received deduction.

Distributions of net capital gain (the excess of net long-term capital gain over net short-term capital loss), if any, properly reported as capital gain dividends are taxable to a shareholder as long-term capital gains, regardless of how long the shareholder has held Fund shares. An election may be available to you to defer recognition of the gain attributable to a capital gain dividend if you make certain qualifying investments within a limited time.  You should talk to your tax advisor about the availability of this deferral election and its requirements. Shareholders receiving distributions in the form of additional shares, rather than cash, generally will have a tax basis in each such share equal to the value of a share of a Fund on the reinvestment date. A distribution of an amount in excess of a Fund's current and accumulated earnings and profits will be treated by a shareholder as a return of capital which is applied against and reduces the shareholder’s basis in his or her shares. To the extent that the amount of any such distribution exceeds the shareholder’s basis in his or her shares, the excess will be treated by the shareholder as gain from a sale or exchange of the shares.

Shareholders will be notified annually as to the U.S. federal income tax status of distributions and shareholders receiving distributions in the form of additional shares will receive a report as to the value of those shares.

Sale or Exchange of Fund Shares

Upon the sale or other disposition of shares of a Fund, which a shareholder holds as a capital asset, such shareholder may realize a capital gain or loss which will be long-term or short-term, depending upon the shareholder’s holding period for the shares. Generally, a shareholder’s gain or loss will be a long-term gain or loss if the shares have been held for more than one year. An election may be available to you to defer recognition of capital gain if you make certain qualifying investments within a limited time.  You should talk to your tax advisor about the availability of this deferral election and its requirements.

Any loss realized on a sale or exchange will be disallowed to the extent that shares disposed of are replaced (including through reinvestment of dividends) within a period of 61 days beginning 30 days before and ending 30 days after disposition of shares or to the extent that the shareholder, during such period, acquires or enters into an option or contract to acquire substantially identical stock or securities. In such a case, the basis of the shares acquired will be adjusted to reflect the disallowed loss. Any loss realized by a shareholder on a disposition of Fund shares held by the shareholder for six months or less will be treated as a long-term capital loss to the extent of any distributions of long-term capital gain received by the shareholder with respect to such shares.

Taxes on Purchase and Redemption of Creation Units

If a shareholder exchanges securities for Creation Units, the shareholder will generally recognize a gain or a loss. The gain or loss will be equal to the difference between the market value of the Creation Units at the time and the shareholder’s aggregate basis in the securities surrendered and the Cash Component paid. If a shareholder exchanges Creation Units for securities, then the shareholder will generally recognize a gain or loss equal to the difference between the shareholder’s basis in the Creation Units and the aggregate market value of the securities received and the Cash Redemption Amount. The IRS, however, may assert that a loss realized upon an exchange of securities for Creation Units or Creation Units for securities cannot be deducted currently under the rules governing “wash sales,” or on the basis that there has been no significant change in economic position.

Nature of Fund Investments

Certain of the Funds' investment practices are subject to special and complex federal income tax provisions that may, among other things, (i) disallow, suspend or otherwise limit the allowance of certain losses or deductions; (ii) convert lower taxed long-term capital gain into higher taxed short-term capital gain or ordinary income; (iii) convert an ordinary loss or a deduction into a capital loss (the deductibility of which is more limited); (iv) cause a Fund to recognize income or gain without a corresponding receipt of cash; (v) adversely affect the time as to when a purchase or sale of stock or securities is deemed to occur; and (vi) adversely alter the characterization of certain complex financial transactions.

Futures Contracts and Options

The Funds' transactions in futures contracts and options will be subject to special provisions of the Code that, among other things, may affect the character of gains and losses realized by a Fund (i.e., may affect whether gains or losses

49

are ordinary or capital, or short-term or long-term), may accelerate recognition of income to a Fund and may defer Fund losses. These rules could, therefore, affect the character, amount and timing of distributions to shareholders. These provisions also (i) will require a Fund to mark-to-market certain types of the positions in its portfolio (i.e., treat them as if they were closed out); and (ii) may cause a Fund to recognize income without receiving cash with which to make distributions in amounts necessary to satisfy the 90% distribution requirement for qualifying to be taxed as a RIC and the distribution requirements for avoiding excise taxes.

Investments in Certain Foreign Corporations

If a Fund holds an equity interest in any “passive foreign investment companies” (“PFICs”), which are generally certain foreign corporations that receive at least 75% of their annual gross income from passive sources (such as interest, dividends, certain rents and royalties or capital gains) or that hold at least 50% of their assets in investments producing such passive income, the Fund could be subject to U.S. federal income tax and additional interest charges on gains and certain distributions with respect to those equity interests, even if all the income or gain is timely distributed to its shareholders. A Fund will not be able to pass through to its shareholders any credit or deduction for such taxes. A Fund may be able to make an election that could ameliorate these adverse tax consequences. In this case, a Fund would recognize as ordinary income any increase in the value of such PFIC shares, and as ordinary loss any decrease in such value to the extent it did not exceed prior increases included in income. Under this election, a Fund might be required to recognize in a year income in excess of its distributions from PFICs and its proceeds from dispositions of PFIC stock during that year, and such income would nevertheless be subject to the distribution requirement and would be taken into account for purposes of the 4% excise tax (described above). Dividends paid by PFICs are not treated as qualified dividend income.

Backup Withholding

A Fund may be required to withhold U.S. federal income tax from all taxable distributions and sale proceeds payable to shareholders who fail to provide the Fund with their correct taxpayer identification number or fail to make required certifications, or who have been notified by the IRS that they are subject to backup withholding. Corporate shareholders and certain other shareholders specified in the Code generally are exempt from such backup withholding. This withholding is not an additional tax. Any amounts withheld may be credited against the shareholder’s U.S. federal income tax liability.

Non-U.S. Shareholders

U.S. taxation of a shareholder who, as to the United States, is a nonresident alien individual, a foreign trust or estate, a foreign corporation or foreign partnership (“non-U.S. shareholder”) depends on whether the income of a Fund is “effectively connected” with a U.S. trade or business carried on by the shareholder.

In addition to the rules described in this section concerning the potential imposition of withholding on distributions to non-U.S. persons, distributions to non-U.S. persons that are “financial institutions” may be subject to a withholding tax of 30% unless an agreement is in place between the financial institution and the U.S. Treasury to collect and disclose information about accounts, equity investments or debt interests in the financial institution held by one or more U.S. persons or the institution is resident in a jurisdiction that has entered into such an agreement with the U.S. Treasury. For these purposes, a “financial institution” means any entity that (i) accepts deposits in the ordinary course of a banking or similar business; (ii) holds financial assets for the account of others as a substantial portion of its business; or (iii) is engaged (or holds itself out as being engaged) primarily in the business of investing, reinvesting or trading in securities, partnership interests, commodities or any interest (including a futures contract or option) in such securities, partnership interests or commodities. This withholding tax is also currently scheduled to apply to the gross proceeds from the disposition of securities that produce U.S. source interest or dividends. However, proposed regulations may eliminate the requirement to withhold on payments of gross proceeds from dispositions.

Distributions to non-financial non-U.S. entities (other than publicly traded foreign entities, entities owned by residents of U.S. possessions, foreign governments, international organizations or foreign central banks) will also be subject to a withholding tax of 30% if the entity does not certify that the entity does not have any substantial U.S. owners or provide the name, address and TIN of each substantial U.S. owner. This withholding tax is also currently scheduled to apply to the gross proceeds from the disposition of securities that produce U.S. source interest or dividends. However, proposed regulations may eliminate the requirement to withhold on payments of gross proceeds from dispositions.

50

Income Not Effectively Connected. If the income from a Fund is not “effectively connected” with a U.S. trade or business carried on by the non-U.S. shareholder, distributions of investment company taxable income will generally be subject to a U.S. tax of 30% (or lower treaty rate), which tax is generally withheld from such distributions.

Distributions of capital gain dividends and any amounts retained by a Fund which are properly reported by the Fund as undistributed capital gains will not be subject to U.S. tax at the rate of 30% (or lower treaty rate) unless the non-U.S. shareholder is a nonresident alien individual and is physically present in the United States for more than 182 days during the taxable year and meets certain other requirements. However, this 30% tax on capital gains of nonresident alien individuals who are physically present in the United States for more than the 182 day period only applies in exceptional cases because any individual present in the United States for more than 182 days during the taxable year is generally treated as a resident for U.S. income tax purposes; in that case, he or she would be subject to U.S. income tax on his or her worldwide income at the graduated rates applicable to U.S. citizens, rather than the 30% U.S. tax. In the case of a non-U.S. shareholder who is a nonresident alien individual, a Fund may be required to withhold U.S. income tax from distributions of net capital gain unless the non-U.S. shareholder certifies his or her non-U.S. status under penalties of perjury or otherwise establishes an exemption. If a non-U.S. shareholder is a nonresident alien individual, any gain such shareholder realizes upon the sale or exchange of such shareholder’s shares of a Fund in the United States will ordinarily be exempt from U.S. tax unless the gain is U.S. source income and such shareholder is physically present in the United States for more than 182 days during the taxable year and meets certain other requirements.

Distributions from a Fund that are properly reported by the Fund as an interest-related dividend attributable to certain interest income received by the Fund or as a short-term capital gain dividend attributable to certain net short-term capital gain income received by a Fund may not be subject to U.S. federal income taxes, including withholding taxes when received by certain non-U.S. shareholders, provided that each Fund makes certain elections and certain other conditions are met. For tax years after December 31, 2022, amounts paid to or recognized by a non-U.S. affiliate that are excluded from tax under the portfolio interest, capital gain dividends, short-term capital gains or tax-exempt interest dividend exceptions or applicable treaties, may be taken into consideration in determining whether a corporation is an “applicable corporation” subject to a 15% minimum tax on adjusted financial statement income. 

In addition, capital gain distributions attributable to gains from U.S. real property interests (including certain U.S. real property holding corporations) will generally be subject to United States withholding tax and will give rise to an obligation on the part of the non-U.S. shareholder to file a United States tax return.

Income Effectively Connected. If the income from a Fund is “effectively connected” with a U.S. trade or business carried on by a non-U.S. shareholder, then distributions of investment company taxable income and capital gain dividends, any amounts retained by the Fund which are properly reported by the Fund as undistributed capital gains and any gains realized upon the sale or exchange of shares of the Fund will be subject to U.S. income tax at the graduated rates applicable to U.S. citizens, residents and domestic corporations. Non-U.S. corporate shareholders may also be subject to the branch profits tax imposed by the Code. The tax consequences to a non-U.S. shareholder entitled to claim the benefits of an applicable tax treaty may differ from those described herein. Non-U.S. shareholders are advised to consult their own tax advisors with respect to the particular tax consequences to them of an investment in a Fund.

Capital Loss Carry-forward

Under the Regulated Investment Company Modernization Act of 2010, net capital losses of a Fund incurred in taxable years beginning after December 22, 2010 may be carried forward indefinitely, and their character is retained as short-term and/or long-term losses. To the extent that these loss carry-forwards are used to offset future capital gains, it is probable that the capital gains so offset will not be distributed to Fund shareholders. As of July 31, 2024, the Funds had post-enactment capital losses for federal income tax purposes as shown in the following table. The Funds are subject to certain limitations, under U.S. tax rules, on the use of capital loss carry-forwards and net unrealized built-in losses. These limitations generally apply when there has been a 50% change in ownership. 

Fund	Total Non-Expiring Capital Loss Available
First Trust Consumer Discretionary AlphaDEX® Fund	$466,684,533
First Trust Consumer Staples AlphaDEX® Fund	295,226,113

51

Fund	Total Non-Expiring Capital Loss Available
First Trust Energy AlphaDEX® Fund	523,492,898
First Trust Financials AlphaDEX® Fund	488,528,414
First Trust Health Care AlphaDEX® Fund	745,021,536
First Trust Industrials/Producer Durables AlphaDEX® Fund	382,225,506
First Trust Materials AlphaDEX® Fund	297,989,820
First Trust Technology AlphaDEX® Fund	622,183,753
First Trust Utilities AlphaDEX® Fund	209,372,648
First Trust Large Cap Core AlphaDEX® Fund	278,103,907
First Trust Mid Cap Core AlphaDEX® Fund	303,630,402
First Trust Small Cap Core AlphaDEX® Fund	360,738,367
First Trust Large Cap Value AlphaDEX® Fund	257,138,317
First Trust Large Cap Growth AlphaDEX® Fund	241,855,966
First Trust Multi Cap Value AlphaDEX® Fund	48,075,386
First Trust Multi Cap Growth AlphaDEX® Fund	72,140,268
First Trust Mid Cap Value AlphaDEX® Fund	60,438,900
First Trust Mid Cap Growth AlphaDEX® Fund	158,065,926
First Trust Small Cap Value AlphaDEX® Fund	66,852,224
First Trust Small Cap Growth AlphaDEX® Fund	183,227,660

Other Taxation

Fund shareholders may be subject to state, local and foreign taxes on their Fund distributions. Shareholders are advised to consult their own tax advisors with respect to the particular tax consequences to them of an investment in the Funds.

Determination of Net Asset Value

Each Fund’s net asset value is determined as set forth in the Prospectus in the section entitled “Net Asset Value.”

Dividends and Distributions

The following information supplements and should be read in conjunction with the section in the Prospectus entitled “Dividends, Distributions and Taxes.”

General Policies. Dividends from net investment income of a Fund, if any, are declared and paid quarterly. Distributions of net realized securities gains, if any, generally are declared and paid once a year, but the Trust may make distributions on a more frequent basis. The Trust reserves the right to declare special distributions if, in its reasonable discretion, such action is necessary or advisable to preserve the status of each Fund as a RIC or to avoid imposition of income or excise taxes on undistributed income.

Dividends and other distributions of Fund shares are distributed, as described below, on a pro rata basis to Beneficial Owners of such shares. Dividend payments are made through DTC Participants and Indirect Participants to Beneficial Owners then of record with proceeds received from the Funds.

Dividend Reinvestment Service. No reinvestment service is provided by the Trust. Broker-dealers may make available the DTC book-entry Dividend Reinvestment Service for use by Beneficial Owners of the Funds for reinvestment of their dividend distributions. Beneficial Owners should contact their brokers in order to determine the availability and costs of the service and the details of participation therein. Brokers may require Beneficial Owners to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and realized gains will be automatically reinvested in additional whole shares of each Fund purchased in the secondary market.

52

Miscellaneous Information

Counsel. Chapman and Cutler LLP, 320 South Canal St., Chicago, Illinois 60606, is counsel to the Trust.

Independent Registered Public Accounting Firm. Deloitte & Touche LLP, 111 South Wacker Drive, Chicago, Illinois 60606, serves as the Funds' independent registered public accounting firm. The firm audits the Funds' financial statements and performs other related audit services.

Financial Statements

The audited financial statements and notes thereto for the Funds, contained in the Form N-CSR dated July 31, 2024, are incorporated by reference into this Statement of Additional Information and have been audited by Deloitte & Touche LLP, independent registered public accounting firm, whose report also appears in the Form N-CSR and is also incorporated by reference herein. No other parts of the Form N-CSR are incorporated by reference herein. The Form N-CSR is available without charge by calling (800) 621-1675 or by visiting the SEC's website at http://www.sec.gov.

53

Exhibit A—Principal Holders Table 

NAME OF BENEFICIAL OWNER	% OF OUTSTANDING SHARES OWNED
FIRST TRUST CONSUMER DISCRETIONARY ALPHADEX® FUND
BNYMellon/Re ETF - UIT DTC/NSCC 0963	49.76%
Wells Fargo Clearing Services, LLC	9.38%
Morgan Stanley Smith Barney LLC	7.47%
Charles Schwab & Co., Inc.	7.31%
FIRST TRUST CONSUMER STAPLES ALPHADEX® FUND
Citibank, N.A.	14.93%
Charles Schwab & Co., Inc.	13.35%
LPL Financial LLC	11.52%
Morgan Stanley Smith Barney LLC	10.90%
National Financial Services LLC	9.36%
Wells Fargo Clearing Services, LLC	6.44%
Pershing LLC	6.38%
Raymond James & Associates, Inc.	6.03%
FIRST TRUST ENERGY ALPHADEX® FUND
LPL Financial LLC	14.90%
Wells Fargo Clearing Services, LLC	13.49%
Morgan Stanley Smith Barney LLC	13.19%
Charles Schwab & Co., Inc.	12.67%
National Financial Services LLC	6.83%
UBS Financial Services Inc.	6.74%
Raymond James & Associates, Inc.	6.34%
FIRST TRUST FINANCIALS ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	15.49%
Charles Schwab & Co., Inc.	15.34%
Wells Fargo Clearing Services, LLC	11.29%
LPL Financial LLC	10.51%
National Financial Services LLC	9.96%
Raymond James & Associates, Inc.	6.70%
UBS Financial Services Inc.	5.09%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	5.08%
FIRST TRUST HEALTH CARE ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	19.94%
Charles Schwab & Co., Inc.	12.13%
National Financial Services LLC	9.48%
Wells Fargo Clearing Services, LLC	9.05%
Raymond James & Associates, Inc.	7.49%
LPL Financial LLC	7.17%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	5.39%

A-1

NAME OF BENEFICIAL OWNER	% OF OUTSTANDING SHARES OWNED
FIRST TRUST INDUSTRIALS/PRODUCER DURABLES ALPHADEX® FUND
BNYMellon/Re ETF - UIT DTC/NSCC 0963	40.82%
Wells Fargo Clearing Services, LLC	9.64%
Charles Schwab & Co., Inc.	8.82%
Morgan Stanley Smith Barney LLC	8.30%
LPL Financial LLC	5.92%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	5.84%
FIRST TRUST MATERIALS ALPHADEX® FUND
Wells Fargo Clearing Services, LLC	15.56%
Charles Schwab & Co., Inc.	13.87%
National Financial Services LLC	10.05%
LPL Financial LLC	7.58%
Morgan Stanley Smith Barney LLC	7.33%
Raymond James & Associates, Inc.	7.26%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	6.92%
Pershing LLC	5.74%
FIRST TRUST TECHNOLOGY ALPHADEX® FUND
Charles Schwab & Co., Inc.	14.33%
Morgan Stanley Smith Barney LLC	11.99%
Wells Fargo Clearing Services, LLC	11.92%
National Financial Services LLC	11.36%
Raymond James & Associates, Inc.	9.76%
LPL Financial LLC	8.19%
FIRST TRUST UTILITIES ALPHADEX® FUND
Charles Schwab & Co., Inc.	16.92%
Morgan Stanley Smith Barney LLC	15.18%
National Financial Services LLC	13.96%
LPL Financial LLC	8.74%
Raymond James & Associates, Inc.	8.13%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	7.28%
Pershing LLC	6.22%
Wells Fargo Clearing Services, LLC	6.19%
FIRST TRUST LARGE CAP CORE ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	15.39%
National Financial Services LLC	13.26%
Charles Schwab & Co., Inc.	13.09%
LPL Financial LLC	11.07%
Raymond James & Associates, Inc.	8.33%
Wells Fargo Clearing Services, LLC	7.65%

A-2

NAME OF BENEFICIAL OWNER	% OF OUTSTANDING SHARES OWNED
FIRST TRUST LARGE CAP GROWTH ALPHADEX® FUND
LPL Financial LLC	13.81%
Morgan Stanley Smith Barney LLC	13.75%
National Financial Services LLC	9.90%
Charles Schwab & Co., Inc.	7.94%
Wells Fargo Clearing Services, LLC	7.79%
Raymond James & Associates, Inc.	7.44%
Pershing LLC	6.95%
Janney Montgomery Scott LLC	5.83%
UBS Financial Services Inc.	5.47%
FIRST TRUST LARGE CAP VALUE ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	18.54%
National Financial Services LLC	12.02%
Charles Schwab & Co., Inc.	11.59%
LPL Financial LLC	11.50%
Raymond James & Associates, Inc.	9.31%
Pershing LLC	8.34%
UBS Financial Services Inc.	8.34%
FIRST TRUST MID CAP CORE ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	15.67%
LPL Financial LLC	13.68%
Wells Fargo Clearing Services, LLC	11.94%
National Financial Services LLC	9.78%
Charles Schwab & Co., Inc.	8.68%
Raymond James & Associates, Inc.	7.53%
Pershing LLC	6.38%
FIRST TRUST MID CAP GROWTH ALPHADEX® FUND
LPL Financial LLC	21.36%
Wells Fargo Clearing Services, LLC	16.16%
Raymond James & Associates, Inc.	10.99%
Morgan Stanley Smith Barney LLC	10.14%
Charles Schwab & Co., Inc.	9.54%
National Financial Services LLC	8.30%
Pershing LLC	7.07%
UBS Financial Services Inc.	5.18%
FIRST TRUST MID CAP VALUE ALPHADEX® FUND
Charles Schwab & Co., Inc.	33.08%
National Financial Services LLC	16.48%
LPL Financial LLC	12.40%
Wells Fargo Clearing Services, LLC	8.55%
Morgan Stanley Smith Barney LLC	7.64%

A-3

NAME OF BENEFICIAL OWNER	% OF OUTSTANDING SHARES OWNED
FIRST TRUST MULTI CAP GROWTH ALPHADEX® FUND
Morgan Stanley Smith Barney LLC	13.24%
National Financial Services LLC	12.83%
Raymond James & Associates, Inc.	12.46%
Charles Schwab & Co., Inc.	10.82%
LPL Financial LLC	10.64%
Edward Jones	6.82%
Pershing LLC	5.63%
FIRST TRUST MULTI CAP VALUE ALPHADEX® FUND
Raymond James & Associates, Inc.	12.62%
National Financial Services LLC	10.24%
Pershing LLC	9.44%
LPL Financial LLC	9.27%
Morgan Stanley Smith Barney LLC	8.21%
Charles Schwab & Co., Inc.	7.83%
Janney Montgomery Scott LLC	7.66%
Wells Fargo Clearing Services, LLC	6.32%
Edward Jones	5.86%
FIRST TRUST SMALL CAP CORE ALPHADEX® FUND
LPL Financial LLC	12.49%
Morgan Stanley Smith Barney LLC	11.72%
Wells Fargo Clearing Services, LLC	10.67%
Charles Schwab & Co., Inc.	10.16%
National Financial Services LLC	9.09%
Raymond James & Associates, Inc.	7.84%
Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB	5.88%
RBC Capital Markets, LLC	5.78%
UBS Financial Services Inc.	5.67%
FIRST TRUST SMALL CAP GROWTH ALPHADEX® FUND
LPL Financial LLC	19.90%
Charles Schwab & Co., Inc.	12.37%
Pershing LLC	10.60%
Raymond James & Associates, Inc.	8.76%
Wells Fargo Clearing Services, LLC	7.75%
Morgan Stanley Smith Barney LLC	7.65%
National Financial Services LLC	6.79%
BNYMellon/Re ETF - UIT DTC/NSCC 0963	5.37%

A-4

NAME OF BENEFICIAL OWNER	% OF OUTSTANDING SHARES OWNED
FIRST TRUST SMALL CAP VALUE ALPHADEX® FUND
Charles Schwab & Co., Inc.	15.74%
LPL Financial LLC	14.83%
National Financial Services LLC	13.64%
Wells Fargo Clearing Services, LLC	11.91%
Raymond James & Associates, Inc.	8.63%
Morgan Stanley Smith Barney LLC	8.26%

(1)

BNYMellon/Re ETF - UIT DTC/NSCC 0963: 525 William Penn Place, Suite 153-0400, Pittsburgh, Pennsylvania 15259

(2)

Charles Schwab & Co., Inc.: 2423 E Lincoln Drive, Phoenix, Arizona 85016

(3)

Citibank, N.A.: 3801 Citibank Center, B/3Rd Floor/Zone 12, Tampa, Florida 33610

(4)

Edward Jones: 201 Progress Parkway, Maryland Heights, Missouri 63043-3042

(5)

Janney Montgomery Scott LLC: C/O Mediant Communications Inc, 200 Regency Forest Drive, Cary, North Carolina 27518

(6)

LPL Financial LLC: 1055 LPL Way, Fort Mill, South Carolina 29715

(7)

Merrill Lynch, Pierce, Fenner & Smith Incorporated/8862 MLPF&S TS SUB: 4804 Deer Lake Dr E, Jacksonville, Florida 32246

(8)

Morgan Stanley Smith Barney LLC: 1300 Thames St, 6th Floor, Baltimore, Maryland 21231

(9)

National Financial Services LLC: 499 Washington Boulevard, Jersey City, New Jersey 07310

(10)

Pershing LLC: One Pershing Plaza, Jersey City, New Jersey 07399

(11)

Raymond James & Associates, Inc.: 880 Carillon Parkway, St. Petersburg, Florida 33716

(12)

RBC Capital Markets, LLC: 60 S 6th Street, P-09, Minneapolis, Minnesota 55402

(13)

UBS Financial Services Inc.: 1000 Harbor Blvd, Weehawken, New Jersey 07086

(14)

Wells Fargo Clearing Services, LLC: 2801 Market Street, H0006-09B, St. Louis, Missouri 63103

A-5

Exhibit B—Proxy Voting Policies and Procedures

FIRST TRUST ADVISORS L.P.
PROXY VOTING POLICIES AND PROCEDURES

First Trust Advisors L.P. (“FTA” or the “Adviser”) serves as investment adviser to open- and closed-end investment companies, and other collective investments (“Funds”), as well as separately managed accounts (collectively, “Clients”). As part of these services, the Adviser has, in most cases, agreed to or been delegated proxy voting responsibility on such Clients’ behalf (“Proxy Clients”). FTA is required to adopt and implement policies and procedures reasonably designed to ensure proxy voting on behalf of Proxy Clients is conducted in a manner that is in their best interests and addresses how conflicts of interest between FTA’s interests and Proxy Clients’ interests are managed. FTA has adopted the following policies and procedures to comply with this requirement (the “Policy”).

(1)

It is the Adviser’s policy to seek and to ensure that proxies are voted consistently and in the best economic interests of the Proxy Client. The FTA Investment Committee is responsible for the implementation of the Policy.

(2)

The Adviser engaged Institutional Shareholder Services (“ISS”) to provide proxy research, recommendations, and voting services. ISS provides a password protected website which is accessible to authorized FTA personnel to download upcoming proxy meeting data, including research reports of companies held in Proxy Client portfolios. The website can be used to view proposed proxy votes and to enter votes for upcoming meetings for Proxy Client portfolio securities.

(3)

FTA will generally follow the ISS Proxy Voting Guidelines (the “Guidelines”) to vote proxies for Proxy Clients’ accounts, so long as such Guidelines are considered to be in the best interests of the Proxy Client, and there are no noted or perceived conflicts of interest. FTA’s use of the Guidelines is not intended to constrain FTA’s consideration of any proxy proposal, and there are times when FTA deviates from the Guidelines, including but not limited to: (i) when required by Rule 12d1-4 agreements between Fund Proxy Clients and certain acquired funds, if applicable and (ii) not withhold votes or not vote against directors solely based on quota criteria. When FTA deviates from the Guidelines, FTA will consider such proxy voting decisions in light of merit-based considerations which it believes may impact shareholder value. The Guidelines are posted on the “News and Literature” page on the website (http://www.ftportfolios.com) for each Fund for which FTA votes proxies.

(4)

FTA will also vote against shareholder proposals that are not related to a company’s core business and/or do not appear to be an appropriate use of a company’s resources to maximize shareholder value.

(5)

FTA may vote against the Guidelines in other circumstances as it has final authority and fiduciary responsibility for proxy voting.

(6)

In certain circumstances, where FTA has determined that it is consistent with Proxy Clients’ best interests, FTA will not vote a proxy on behalf of one or more Proxy Clients. Such circumstances include:

(a)

Limited Value. Proxies will not be required to be voted on securities in a Proxy Client’s account if the value of the Proxy Client’s economic interest in the securities is indeterminable or insignificant (less than $1,000). Proxies will also not be required to be voted for any securities that are no longer held in Proxy Client’s account(s).

(b)

Securities Lending Program. When Fund portfolio securities are out on loan, they are transferred into the borrower’s name and are voted by the borrower, in its discretion. In most cases, FTA will not recall securities on loan in order to vote a proxy. However, where FTA determines that a proxy vote, or other shareholder action, is materially important to the Fund Proxy Client’s account, FTA will make a good faith effort to recall the security for purposes of voting, understanding that in certain cases, the attempt to recall the security may not be effective in time to meet voting deadlines. In certain instances, in FTA’s discretion, disclosure regarding FTA’s process for determining whether or not to recall Fund portfolio securities on loan for proxy voting purposes may be provided as part of the Funds’ annual Form N-PX filing.

B-1

(c)

Unjustifiable Costs. In certain circumstances, based on cost-benefit analysis, FTA may choose not to vote when the cost of voting on behalf of a Proxy Client would exceed any anticipated benefits of the proxy proposal to such Proxy Client (e.g. foreign securities).

(d)

International Markets Share Blocking. Share blocking is the “freezing” of shares for trading purposes at the custodian/sub-custodian bank level in order to vote proxies. While shares are frozen, they may not be traded. Therefore, the potential exists for a pending trade to fail if trade settlement falls on a date during the blocking period. In international markets where share blocking applies, FTA typically will not, but reserves the right to, vote proxies due to the liquidity constraints associated with share blocking.

(7)

On a regular basis, FTA Research reviews ISS recommendations on matters determined to have a potential impact of shareholder value to decide whether to vote as the Guidelines recommend and advises the FTA Investment Committee of its determination.

(8)

FTA may determine voting in accordance with the Guidelines is not in the best interests of a Proxy Client. If there is a decision to vote against the Guidelines, the FTA Investment Committee will document the reason and instruct ISS to change the vote to reflect this decision.

(9)

Whenever a conflict of interest arises between ISS and a target company subject to a proxy vote, the Adviser will consider the recommendation of the company and what the Adviser believes to be in the best interests of the Proxy Client and will vote the proxy without using the Guidelines. If FTA has knowledge of a material conflict of interest between itself and a Proxy Client, the Adviser shall vote the applicable proxy in accordance with the Guidelines to avoid such conflict of interest. If there is a conflict of interest between a Fund Proxy Client and FTA or other Fund service providers, FTA will vote the proxy based on the Guidelines to avoid such conflict of interest.

(10)

If a Proxy Client requests the Adviser to follow specific voting guidelines or additional guidelines, the Adviser shall review the request and follow such guidelines, unless the Adviser determines that it is unable to do so. In such case, the Adviser shall inform the Proxy Client that it is not able to honor the Proxy Client’s request.

(11)

FTA periodically reviews proxy votes to ensure compliance with this Policy.

(12)

This Policy, the Guidelines and votes cast for Proxy Clients are available upon request and such Proxy Client requests must be forwarded to FTA Compliance for review and response. This Policy is also provided with each advisory contract and described and provided with the Form ADV, Part 2A.

Shareholders of Fund Proxy Clients can review the Policy and a Fund’s voted proxies (if any) during the most recent 12-month period ended June 30 on the First Trust website at http://www.ftportfolios.com or by accessing EDGAR on the SEC website at http://www.sec.gov.

(13)

FTA provides reasonable ongoing oversight of ISS. FTA, or ISS on behalf of FTA, maintains the following records relating to proxy voting:

(a)

a copy of this Policy;

(b)

a copy of each proxy form for which it is responsible to vote;

(c)

a copy of each proxy solicitation, including proxy statements and related materials with regard to each proxy issue it votes;

(d)

documents relating to the identification and resolution of conflicts of interest, if any;

(e)

any documents created by FTA or ISS that were material to a proxy voting decision or that memorialized the basis for that decision; and

(f)

a copy of each written request from any Proxy Client for information on how FTA voted proxies on the Proxy Client’s behalf, and a copy of any written response by FTA to any written or oral request for information by a Proxy Client on how FTA voted proxies for that Proxy Client’s account.

B-2

These records are either maintained at FTA’s office or are electronically available to FTA through access to the ISS Proxy Exchange portal.

Adopted: September 15, 2003
Amended: December 10, 2007
Amended: September 21, 2009
Amended: September 12, 2016
Amended: March 9, 2020
Amended: June 7, 2021
Amended: January 19, 2022
Amended: May 13, 2022
Amended: September 22, 2022
Amended: July 3, 2023
Amended: January 10, 2024

B-3

 

Part C – Other Information

Item 28. Exhibits

Exhibit No. Description

(a) Amended and Restated Declaration of Trust is incorporated by reference to the Post-Effective Amendment No. 36 filed on Form N-1A (File No. 333-140895) for Registrant on November 28, 2017.

(b) By-Laws of the Registrant is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(c) Amended and Restated Establishment and Designation of Series is incorporated by reference to the Post-Effective Amendment No. 9 filed on Form N-1A (File No. 333-140895) for Registrant on March 25, 2011.

(d) (1) Investment Management Agreement (Expense Cap Funds) is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 22, 2013.

(2) Investment Management Agreement (Unitary Fee Funds) is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 22, 2013.

(3) Amended Expense Reimbursement, Fee Waiver and Recovery Agreement is filed herewith.

(e) (1) Distribution Agreement between the Registrant and First Trust Portfolios L.P. is incorporated by reference to the Post-Effective Amendment No. 7 filed on Form N-1A (File No. 333-140895) for Registrant on November 29, 2010.

(2) Amended Exhibit A to Distribution Agreement is incorporated by reference to the Post-Effective Amendment No. 18 filed on Form N-1A (File No. 333-140895) for Registrant on May 10, 2011.

(f) Not Applicable

(g) (1) Custody Agreement between the Registrant and The Bank of New York is incorporated by reference to the Post-Effective Amendment No. 1 filed on Form N-1A (File No. 333-140895) for Registrant on November 19, 2007.

(2) Amended Schedule II to the Custody Agreement between the Registrant and The Bank of New York is incorporated by reference to the Post-Effective Amendment No. 10 filed on Form N-1A (File No. 333-140895) for Registrant on May 10, 2011.

(h) (1) Transfer Agency Agreement between the Registrant and The Bank of New York dated May 4, 2007, is incorporated by reference to the Post-Effective Amendment No. 1 filed on Form N-1A (File No. 333-140895) for Registrant on November 19, 2007.

(2) Amended Exhibit A to the Transfer Agency Agreement between the Registrant and The Bank of New York is incorporated by reference to the Post-Effective Amendment No. 10 filed on Form N-1A (File No. 333-140895) for Registrant on May 10, 2011.

(3) Administration and Accounting Agreement between the Registrant and The Bank of New York is incorporated by reference to the Post-Effective Amendment No. 1 filed on Form N-1A (File No. 333-140895) for Registrant on November 19, 2007.

(4) Amended Exhibit A to the Administration and Accounting Agreement between the Registrant and The Bank of New York is incorporated by reference to the Post-Effective Amendment No. 10 filed on Form N-1A (File No. 333-140895) for Registrant on May 10, 2011.

(5) Form of Subscription Agreement is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(6) Form of Participant Agreement is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(7) Board Administration Services Agreement among PFPC, Inc., First Trust Exchange-Traded Fund and First Trust Exchange-Traded AlphaDEX^® Fund dated February 15, 2007, is incorporated by reference to First Trust Exchange-Traded Fund’s Post-Effective Amendment No. 39 filed on Form N-1A (File No. 333-125751) on April 27, 2007.

(8) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Consumer Discretionary AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(9) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Consumer Staples AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(10) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Energy AlphaDEX^® Fund dated April 26, 2007. is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(11) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Financials AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(12) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Health Care AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(13) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Industrials AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(14) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Materials AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(15) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Technology AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(16) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Utilities AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(17) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Large Cap Core AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(18) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Mid Cap Core AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(19) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Small Cap Core AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(20) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Large Cap Value Opportunities AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(21) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Large Cap Growth Opportunities AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(22) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Mid Cap Growth Opportunities AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(23) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Multi Cap Value AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(24) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Multi Cap Growth AlphaDEX^® Fund dated April 26, 2007, is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(25) Amendment No. 1 to the Sublicense Agreement dated as of April 26, 2007, by and among First Trust Portfolios L.P., First Trust Advisors L.P., American Stock Exchange LLC and First Trust Industrials/Producer Durables AlphaDEX^® Fund dated May 8, 2007, is incorporated by reference to the Post-Effective Amendment No. 1 filed on Form N-1A (File No. 333-140895) for Registrant on November 19, 2007.

(26) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Mid Cap Value AlphaDEX^® Fund dated April 8, 2011, is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 25, 2013.

(27) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Mid Cap Growth AlphaDEX^® Fund dated April 8, 2011, is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 25, 2013.

(28) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Small Cap Growth AlphaDEX^® Fund dated April 8, 2011, is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 25, 2013.

(29) Sublicense Agreement by and among First Trust Portfolios L.P., First Trust Advisors L.P., Standard & Poor’s, a division of The McGraw-Hill Companies, Inc. and First Trust Small Cap Value AlphaDEX^® Fund dated April 8, 2011, is incorporated by reference to the Post-Effective Amendment No. 21 filed on Form N-1A (File No. 333-140895) for Registrant on November 25, 2013.

(i) Not Applicable

(j) Consent of Independent Registered Public Accounting Firm is filed herewith.

(k) Not Applicable

(l) Not Applicable

(m) (1) 12b-1 Service Plan is incorporated by reference to the Pre-Effective Amendment No. 3 filed on Form N-1A (File No. 333-140895) for Registrant on April 27, 2007.

(2) 12b-1 Plan Extension Letter Agreement is filed herewith.

(n) Not Applicable

(o) Not Applicable

(p) (1) First Trust Advisors L.P. and First Trust Portfolios L.P. Code of Ethics, amended on July 1, 2013, is incorporated by reference to the Post-Effective Amendment No. 38 filed on Form N-1A (File No. 333-140895) for Registrant on November 28, 2018.

(2) First Trust Funds Code of Ethics, amended on October 30, 2013, is incorporated by reference to the Post-Effective Amendment No. 38 filed on Form N-1A (File No. 333-140895) for Registrant on November 28, 2018.

(q) (1) Powers of Attorney of Messrs. Bowen, Erickson, Kadlec, Keith and Nielson dated December 31, 2015, are incorporated by reference to the Post-Effective Amendment No. 27 filed on Form N-1A (File No. 333-176976) for Registrant on February 3, 2016.

(2) Power of Attorney of Ms. Keefe, dated November 1, 2021, is incorporated by reference to the Post-Effective Amendment No. 43 filed on Form N-1A (File No. 333-176976) for Registrant on November 24, 2021.

(3) Powers of Attorney for Ms. Wright dated September 11, 2023, , is incorporated by reference to the Post-Effective Amendment No. 45 filed on Form N-1A (File No. 333-176976) for Registrant on November 28, 2023.

__________________

Item 29. Persons Controlled By or Under Common Control with Registrant

Not Applicable

Item 30. Indemnification

Section 9.5 of the Registrant’s Declaration of Trust provides as follows:

Section 9.5. Indemnification and Advancement of Expenses. Subject to the exceptions and limitations contained in this Section 9.5, every person who is, or has been, a Trustee, officer, or employee of the Trust, including persons who serve at the request of the Trust as directors, trustees, officers, employees or agents of another organization in which the Trust has an interest as a shareholder, creditor or otherwise (hereinafter referred to as a “Covered Person”), shall be indemnified by the Trust to the fullest extent permitted by law against liability and against all expenses reasonably incurred or paid by him or in connection with any claim, action, suit or proceeding in which he becomes involved as a party or otherwise by virtue of his being or having been such a Trustee, director, officer, employee or agent and against amounts paid or incurred by him in settlement thereof.

No indemnification shall be provided hereunder to a Covered Person to the extent such indemnification is prohibited by applicable federal law.

The rights of indemnification herein provided may be insured against by policies maintained by the Trust, shall be severable, shall not affect any other rights to which any Covered Person may now or hereafter be entitled, shall continue as to a person who has ceased to be such a Covered Person and shall inure to the benefit of the heirs, executors and administrators of such a person.

Subject to applicable federal law, expenses of preparation and presentation of a defense to any claim, action, suit or proceeding subject to a claim for indemnification under this Section 9.5 shall be advanced by the Trust prior to final disposition thereof upon receipt of an undertaking by or on behalf of the recipient to repay such amount if it is ultimately determined that he is not entitled to indemnification under this Section 9.5.

To the extent that any determination is required to be made as to whether a Covered Person engaged in conduct for which indemnification is not provided as described herein, or as to whether there is reason to believe that a Covered Person ultimately will be found entitled to indemnification, the Person or Persons making the determination shall afford the Covered Person a rebuttable presumption that the Covered Person has not engaged in such conduct and that there is reason to believe that the Covered Person ultimately will be found entitled to indemnification.

As used in this Section 9.5, the words “claim,” “action,” “suit” or “proceeding” shall apply to all claims, demands, actions, suits, investigations, regulatory inquiries, proceedings or any other occurrence of a similar nature, whether actual or threatened and whether civil, criminal, administrative or other, including appeals, and the words “liability” and “expenses” shall include without limitation, attorneys’ fees, costs, judgments, amounts paid in settlement, fines, penalties and other liabilities.

Item 31. Business and Other Connections of the Investment Adviser

First Trust Advisors L.P. (“First Trust”), investment adviser to the Registrant, serves as adviser or subadviser to various mutual funds, exchange-traded funds and closed-end funds and is the portfolio supervisor of certain unit investment trusts. Its principal address is 120 East Liberty Drive, Wheaton, Illinois 60187.

The principal business of certain of First Trust’s principal executive officers involves various activities in connection with the family of unit investment trusts sponsored by First Trust Portfolios L.P. (“FTP”). FTP’s principal address is 120 East Liberty Drive, Wheaton, Illinois 60187.

Information as to other business, profession, vocation or employment during the past two years of the officers and directors of First Trust is as follows:

Name and Position with First Trust	Employment During Past Two Years
Andrew S. Roggensack, President	Managing Director and President, First Trust
R. Scott Hall, Managing Director	Managing Director, First Trust
David G. McGarel, Chief Investment Officer, Chief Operating Officer and Managing Director	Managing Director; Senior Vice President, First Trust
Kelly C. Dehler,  Chief Compliance Officer	Assistant General Counsel, First Trust
Brian Wesbury, Chief Economist and Senior Vice President	Chief Economist and Senior Vice President, First Trust

Item 32. Principal Underwriter

(a) FTP serves as principal underwriter of the shares of the Registrant, First Trust Exchange-Traded Fund, First Trust Exchange-Traded Fund II, First Trust Exchange-Traded Fund III, First Trust Exchange-Traded Fund IV, First Trust Exchange-Traded Fund V, First Trust Exchange Traded Fund VI, First Trust Exchange-Traded Fund VII, First Trust Exchange-Traded Fund VIII, First Trust Exchange-Traded AlphaDEX^® Fund II, First Trust Variable Insurance Trust and First Trust Series Fund. FTP serves as principal underwriter and depositor of the following investment companies registered as unit investment trusts: the First Trust Combined Series, FT Series (formerly known as the First Trust Special Situations Trust), the First Trust Insured Corporate Trust, the First Trust of Insured Municipal Bonds, and the First Trust GNMA. The name of each director, officer and partner of FTP is provided below.

(b) Positions and Offices with Underwriter.

Name and Principal Business Address*	Positions and Offices with Underwriter	Positions and Offices with Fund
The Charger Corporation	General Partner	None
Grace Partners of DuPage L.P.	Limited Partner	None
James A. Bowen	Chief Executive Officer and Managing Director	Trustee and Chairman of the Board
James M. Dykas	Chief Operating Officer, Controller and Managing Director	President and Chief Executive Officer
Frank L. Fichera	Managing Director	None
Russell J. Graham	Managing Director	None
R. Scott Hall	Managing Director	None
W. Scott Jardine	General Counsel, Secretary and Managing Director	Secretary
Daniel J. Lindquist	Managing Director	Vice President
David G. McGarel	Managing Director	None
Richard A. Olson	Managing Director	None
Marisa Bowen	Managing Director	None
Andrew S. Roggensack	President and Managing Director	None
Kristi A. Maher	Deputy General Counsel	Chief Compliance Officer and Assistant Secretary
* All addresses are 120 East Liberty Drive, Wheaton, Illinois 60187.

(c) Not Applicable

Item 33. Location of Accounts and Records

First Trust, 120 East Liberty Drive, Wheaton, Illinois 60187, maintains the Registrant’s organizational documents, minutes of meetings, contracts of the Registrant and all advisory material of the investment adviser.

Item 34. Management Services

Not Applicable

Item 35. Undertakings

Not Applicable

Signatures

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, duly authorized in the City of Wheaton, and State of Illinois on the 27th day of November, 2024.

First Trust Exchange-Traded AlphaDEX® Fund
By:	/s/ James M. Dykas
	James M. Dykas, President and Chief Executive Officer

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed below by the following persons in the capacities and on the date indicated:

Signature	Title		Date
/s/ James M. Dykas	President and Chief Executive Officer		November 27, 2024
James M. Dykas
/s/ Derek D. Maltbie	Treasurer, Chief Financial Officer and Chief Accounting Officer		November 27, 2024
Derek D. Maltbie
James A. Bowen*	) Trustee )
	)
Richard E. Erickson*	) Trustee )
	)
Thomas R. Kadlec*	) Trustee )
	)
Denise M. Keefe*	) Trustee )
	)
Robert F. Keith*	) Trustee )
	)	By:	/s/ W. Scott Jardine
Niel B. Nielson*	) Trustee )		W. Scott Jardine Attorney-In-Fact
	)		November 27, 2024
Bronwyn Wright*	) Trustee )
	)

* Original powers of attorney dated March 14, 2016 or November 1, 2021 or September 11, 2023, authorizing James A. Bowen, W. Scott Jardine, James M. Dykas, Eric F. Fess and Kristi A. Maher to execute Registrant's Registration Statement, and Amendments thereto, for each of the trustees of the Registrant on whose behalf this Registration Statement is filed, were previously executed, filed as an exhibit and are incorporated by reference herein, or filed herewith.

Index to Exhibits

(d)(3) Amended Expense Reimbursement, Fee Waiver and Recovery Agreement.

(j) Consent of Independent Registered Public Accounting Firm.

(m)(2) 12b-1 Plan Extension Letter Agreement.

 

EX-99.D ADVSR CONTR

Second Amended and Restated Expense Reimbursement and Fee Waiver Agreement

This Second Amended and Restated Expense Reimbursement and Fee Waiver Agreement (this “Agreement”) is entered into between First Trust Exchange-Traded AlphaDEX^® Fund, a Massachusetts business trust (the “Trust”), and First Trust Advisors L.P., an Illinois limited partnership (“FTA”), as of November 1, 2022.

Recitals:

A. Whereas, the Trust is an open-end management investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”), comprised of various exchange-traded funds (each, a “Fund,” and, collectively, the “Funds”) set forth on Exhibit A attached hereto, which may be amended from time to time. Each Fund constitutes a separate exchange-traded fund with its own investment objectives and policies.

B. Whereas, FTA is the investment adviser to the Funds and is responsible for the selection and ongoing monitoring of the securities in the Funds’ portfolios and certain other services necessary for the management of the Funds and is paid an annual management fee by the Funds.

C. Whereas, the Trust and FTA have entered into an expense reimbursement, fee waiver, and recovery agreement dated April 26, 2007, as amended and restated by the amended expense reimbursement, fee waiver and recovery agreement dated as of April 18, 2019, as extended from time to time (the “Prior Expense Reimbursement Agreement”) pursuant to which FTA agreed to waive management fees and reimburse certain expenses to prevent a Fund’s expense ratio from exceeding a particular expense cap for a term provided therein.

D. Whereas, Section 3 of the Prior Expense Reimbursement Agreement provided that FTA may recover a portion of the amount it reimbursed a Fund for up to three years from the date the fee or expense was incurred during the Expense Cap Term (as defined therein) to the extent such restitution would not cause a Fund to exceed the specified expense cap.

E. Whereas, FTA proposes to continue to waive management fees and reimburse certain expenses to prevent a Fund’s Expense Ratio (as defined below) from exceeding a particular expense cap and to eliminate its ability to seek restitution for any fees waived during the term of this Agreement or the Prior Expense Reimbursement Agreement.

Now, Therefore, in consideration of the foregoing facts and other good and valuable consideration, the parties hereto hereby agree as follows:

Section 1. Definitions. The following terms shall have the following definitions in this Agreement:

-1- 

“Expense Ratio” is defined as a Fund’s annual investment management fees and expenses (excluding taxes, interest, all brokerage commissions, other normal charges incident to the purchase and sale of portfolio securities, and extraordinary expenses) as a percentage of such Fund’s daily net asset value.

“Expense Cap” shall be equal to an Expense Ratio for the Funds as set forth on Exhibit A.

Section 2. Waiver of Fees and Reimbursement of Expenses. On a Fund by Fund basis, FTA will waive investment management fees payable to it by a Fund and/or reimburse a Fund for other expenses borne by such Fund up to such Fund’s respective Expense Cap set forth in Exhibit A for the term set forth in Exhibit A (the “Expense Cap Term”). The aggregate amount of investment management fees waived and expenses reimbursed for a Fund from time to time under this Agreement for a particular Fund shall collectively be referred to as the “Reimbursed Amount.” The Reimbursed Amount shall be accrued and paid on a monthly basis for each Fund but calculated and settled on an annual fiscal year basis.

Section 3. [Reserved].

Section 4. FTA’s fund accounting department shall develop and maintain appropriate internal accounting policies and procedures to monitor and calculate the Reimbursed Amount on a monthly basis for each Fund.

Section 5. Term and Continuation. This Agreement shall be effective on the date provided on Exhibit A (the “Effective Date”) for each respective Fund. This Agreement shall continue in effect for each respective Fund until the end of such Fund’s current Expense Cap Term as set forth on Exhibit A unless the Agreement is continued for additional periods as agreed to by the parties. FTA shall inform the other parties in writing no less than sixty (60) days in advance of the expiration of a Fund’s current Expense Cap Term if it intends not to continue this Agreement for that Fund. This Agreement may be terminated by the Trust on behalf of a Fund at any time on written notice to the other party. Notwithstanding the foregoing, this Agreement shall terminate immediately with respect to a Fund in the event that the investment advisory agreement between such Fund and FTA is either (i) terminated for any reason or (ii) not renewed by the Board of Trustees.

Section 6. Notices. Any notice shall be sufficient when sent by registered or certified mail to the other party at the address of such party, set forth below such party’s signature on this Agreement.

Section 7. Entire Agreement; Amendments. This Agreement supersedes and abrogates all prior understandings, communications and agreements (whether written or oral) between the parties with respect to the subject matter hereof, and this Agreement constitutes the entire agreement between the parties with respect to such subject matter. This Agreement may not be amended except by an instrument in writing signed by each of the parties hereto. No assignment by either party shall be of any force except with the prior written consent of the other party.

-2- 

Section 8. Governing Law; Miscellaneous. This Agreement shall be governed by, and construed in accordance with, the laws of the State of Illinois (without regard to principles of law), including all matters of construction, validity, and performance; provided that nothing herein shall be construed in a manner inconsistent with the 1940 Act or any rule or regulation of the Securities and Exchange Commission. If any provision of this Agreement shall be held or made invalid by a court’s decision, statute, rule or otherwise, the remainder of this Agreement shall not be affected thereby. The captions in this Agreement are included for convenience only and in no way define any of the provisions hereof or otherwise affect their construction or effect. This Agreement shall be binding upon and shall inure to the benefit of the parties hereto and their respective successors.

In Witness Whereof, the parties hereto have executed this Agreement as of the day and year first above written.

First Trust Advisors L.P.		First Trust Exchange-Traded AlphaDEX® Fund
By	/s/ James M. Dykas	By	/s/ James M. Dykas
	Name: James M. Dykas		Name: James M. Dykas
	Title: Chief Financial Officer		Title: President and CEO

Address: First Trust Advisors L.P. 120 E. Liberty Drive Suite 400 Wheaton, Illinois 60187 Fax: (630) 517-7437 Attention: W. Scott Jardine Address: First Trust Advisors L.P. 120 E. Liberty Drive Suite 400 Wheaton, Illinois 60187 Fax: (630) 517-7437 Attention: W. Scott Jardine

-3- 

 Exhibit A

Name of Fund	Expense Cap (of average net assets)	Effective Date	Expense Cap Term
First Trust Consumer Discretionary AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Consumer Staples AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Energy AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Financials AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Health Care AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Industrials/Producer Durables AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Materials AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Technology AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Utilities AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Large Cap Core AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Mid Cap Core AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Small Cap Core AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Large Cap Value AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Large Cap Growth AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Multi Cap Value AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025
First Trust Multi Cap Growth AlphaDEX® Fund	0.70%	October 12, 2010	November 30, 2025

EX-99.J OTHER OPININ

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We consent to the incorporation by reference in this Post-Effective Amendment to Registration Statement No. 333-140895 on Form N-1A of our reports dated September 20, 2024, relating to the financial statements and financial highlights of First Trust Large Cap Core AlphaDEX^® Fund, First Trust Mid Cap Core AlphaDEX^® Fund, First Trust Small Cap Core AlphaDEX^® Fund, First Trust Large Cap Value AlphaDEX^® Fund, First Trust Large Cap Growth AlphaDEX^® Fund, First Trust Multi Cap Value AlphaDEX^® Fund, First Trust Multi Cap Growth AlphaDEX^® Fund, First Trust Mid Cap Value AlphaDEX^® Fund, First Trust Mid Cap Growth AlphaDEX^® Fund, First Trust Small Cap Value AlphaDEX^® Fund, First Trust Small Cap Growth AlphaDEX^® Fund, First Trust Consumer Discretionary AlphaDEX^® Fund, First Trust Consumer Staples AlphaDEX^® Fund, First Trust Energy AlphaDEX^® Fund, First Trust Financials AlphaDEX^® Fund, First Trust Health Care AlphaDEX^® Fund, First Trust Industrials/Producer Durables AlphaDEX^® Fund, First Trust Materials AlphaDEX^® Fund, First Trust Technology AlphaDEX^® Fund, and First Trust Utilities AlphaDEX^® Fund, appearing in Form N-CSR for First Trust Exchange-Traded AlphaDEX^® Fund as of and for the period ended July 31, 2024, and to the references to us under the headings “Financial Highlights” in the Prospectus and “Miscellaneous Information” and “Financial Statements” in the Statement of Additional Information, which are part of such Registration Statement.

/s/ DELOITTE & TOUCHE LLP

Chicago, Illinois

November 26, 2024

EX-99.M 12B-1 PLAN

June 3, 2024

First Trust Exchange-Traded AlphaDEX® Fund

120 East Liberty Drive, Suite 400

Wheaton, Illinois 60187

Re: 12b-1 Plan Extension Letter for First Trust Exchange-Traded AlphaDEX® Fund (the “Trust”).

Ladies and Gentlemen:

It is hereby acknowledged that First Trust Portfolios L.P. serves as the distributor of the shares of each series of the Trust. The Trust is an open-end management investment company registered under the Investment Company Act of 1940, as amended (the “1940 Act”), comprised of various exchange-traded funds (each, a “Fund,” and, collectively, the “Funds”) set forth on Exhibit A attached hereto, which may be supplemented to add new Funds.

It is further acknowledged that the Trust has adopted a Distribution and Service Plan (the “Plan”) pursuant to Rule l2b-1 under the 1940 Act with respect to the shares of beneficial interest (“Shares”) of the Funds. Pursuant to the Plan, each Fund may bear a fee not to exceed 0.25% per annum of such Fund’s average daily net assets.

The purpose of this letter agreement is to agree and acknowledge that the Funds shall not pay, and we shall not collect, any fees pursuant to the Plan any time before the date set forth on Exhibit A attached hereto for each Fund.

Very Truly Yours,

First Trust Portfolios L.P.

/s/ James M. Dykas                         

James M. Dykas

Chief Financial Officer

Agreed and Acknowledged:

First Trust Exchange-Traded AlphaDEX® Fund

 /s/ Donald P. Swade                              

Donald P. Swade

Treasurer, Chief Financial Officer and
Chief Accounting Officer

Exhibit A

FIRST TRUST EXCHANGE-TRADED ALPHADEX^® FUND

Funds	Dates
First Trust Large Cap Core AlphaDEX® Fund	November 30, 2025
First Trust Mid Cap Core AlphaDEX® Fund	November 30, 2025
First Trust Small Cap Core AlphaDEX® Fund	November 30, 2025
First Trust Large Cap Value AlphaDEX® Fund	November 30, 2025
First Trust Large Cap Growth AlphaDEX® Fund	November 30, 2025
First Trust Multi Cap Value AlphaDEX® Fund	November 30, 2025
First Trust Multi Cap Growth AlphaDEX® Fund	November 30, 2025
First Trust Consumer Discretionary AlphaDEX® Fund	November 30, 2025
First Trust Consumer Staples AlphaDEX® Fund	November 30, 2025
First Trust Energy AlphaDEX® Fund	November 30, 2025
First Trust Financials AlphaDEX® Fund	November 30, 2025
First Trust Health Care AlphaDEX® Fund	November 30, 2025
First Trust Industrials/Producer Durables AlphaDEX® Fund	November 30, 2025
First Trust Materials AlphaDEX® Fund	November 30, 2025
First Trust Technology AlphaDEX® Fund	November 30, 2025
First Trust Utilities AlphaDEX® Fund	November 30, 2025
First Trust Mid Cap Growth AlphaDEX® Fund	November 30, 2025
First Trust Mid Cap Value AlphaDEX® Fund	November 30, 2025
First Trust Small Cap Growth AlphaDEX® Fund	November 30, 2025
First Trust Small Cap Value AlphaDEX® Fund	November 30, 2025
First Trust Mega Cap AlphaDEX® Fund	November 30, 2025

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Document Type	dei_DocumentType	485BPOS
Period End Date	dei_DocumentPeriodEndDate	Jul. 31, 2024
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
CIK	dei_EntityCentralIndexKey	0001383496
Amendment Flag	dei_AmendmentFlag	false
Document Creation Date	dei_DocumentCreationDate	Nov. 27, 2024
Document Effective Date	dei_DocumentEffectiveDate	Dec. 02, 2024
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
Entity Inv Company Type	dei_EntityInvCompanyType	N-1A

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Consumer Discretionary AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Consumer Discretionary AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Consumer Discretionary Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 84% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	84.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the consumer discretionary sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 121 securities with a market capitalization range of $1.97 billion to $1.96 trillion. As of October 31, 2024, the Fund had significant investments in consumer discretionary companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 121 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">1.97 billion to $1.96 trillion. As of October 31, 2024, the Fund had significant investments in consumer </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">discretionary companies. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Consumer Discretionary Index (formerly the Russell 1000® Consumer Discretionary and Services Index), on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Consumer Discretionary Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Consumer Discretionary AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.06%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter38.85%June 30, 2020Worst Quarter-40.28%March 31, 2020Year-to-Date8.06%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Consumer Discretionary AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Consumer Discretionary AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Consumer Discretionary AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Consumer Discretionary AlphaDEX Fund | Consumer Discretionary Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CONSUMER DISCRETIONARY COMPANIES RISK. Consumer discretionary companies, such as retailers, media companies and consumer services companies, provide non-essential goods and services. These companies manufacture products and provide discretionary services directly to the consumer, and the success of these companies is tied closely to the performance of the overall domestic and international economy, interest rates, competition and consumer confidence. Success depends heavily on disposable household income and consumer spending. Changes in demographics and consumer tastes can also affect the demand for, and success of, consumer discretionary products in the marketplace.
First Trust Consumer Discretionary AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Consumer Discretionary AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Consumer Discretionary AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Consumer Discretionary AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Consumer Discretionary AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Consumer Discretionary AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Consumer Discretionary AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Consumer Discretionary AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Consumer Discretionary AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Consumer Discretionary AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Consumer Discretionary AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Consumer Discretionary AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Consumer Discretionary AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Consumer Discretionary AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Consumer Discretionary AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Consumer Discretionary AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Consumer Discretionary AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Consumer Discretionary AlphaDEX Fund | First Trust Consumer Discretionary AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.11%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.61%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.61%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 62
3 Years	rr_ExpenseExampleNoRedemptionYear03	195
5 Years	rr_ExpenseExampleNoRedemptionYear05	340
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 762
2014	rr_AnnualReturn2014	11.63%
2015	rr_AnnualReturn2015	(3.81%)
2016	rr_AnnualReturn2016	5.13%
2017	rr_AnnualReturn2017	19.74%
2018	rr_AnnualReturn2018	(11.42%)
2019	rr_AnnualReturn2019	24.16%
2020	rr_AnnualReturn2020	12.92%
2021	rr_AnnualReturn2021	22.68%
2022	rr_AnnualReturn2022	(21.49%)
2023	rr_AnnualReturn2023	23.28%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	8.06%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	38.85%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(40.28%)
1 Year	rr_AverageAnnualReturnYear01	23.28%
5 Years	rr_AverageAnnualReturnYear05	10.73%
10 Years	rr_AverageAnnualReturnYear10	7.14%
Since Inception	rr_AverageAnnualReturnSinceInception	7.56%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Consumer Discretionary AlphaDEX Fund | After tax on distributions | First Trust Consumer Discretionary AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	22.90%
5 Years	rr_AverageAnnualReturnYear05	10.36%
10 Years	rr_AverageAnnualReturnYear10	6.76%
Since Inception	rr_AverageAnnualReturnSinceInception	7.22%
First Trust Consumer Discretionary AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Consumer Discretionary AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.76%
5 Years	rr_AverageAnnualReturnYear05	8.34%
10 Years	rr_AverageAnnualReturnYear10	5.57%
Since Inception	rr_AverageAnnualReturnSinceInception	6.15%
First Trust Consumer Discretionary AlphaDEX Fund | StrataQuant® Consumer Discretionary Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	24.08%
5 Years	rr_AverageAnnualReturnYear05	11.42%
10 Years	rr_AverageAnnualReturnYear10	7.82%
Since Inception	rr_AverageAnnualReturnSinceInception	8.30%
First Trust Consumer Discretionary AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Consumer Discretionary AlphaDEX Fund | S&P 500® Consumer Discretionary Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	42.41%
5 Years	rr_AverageAnnualReturnYear05	13.73%
10 Years	rr_AverageAnnualReturnYear10	11.69%
Since Inception	rr_AverageAnnualReturnSinceInception	11.08%
First Trust Consumer Discretionary AlphaDEX Fund | Russell 1000® Consumer Discretionary Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	36.88%	[2]
5 Years	rr_AverageAnnualReturnYear05	14.10%	[2]
10 Years	rr_AverageAnnualReturnYear10	11.50%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Consumer Discretionary AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Consumer Staples AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Consumer Staples AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Consumer Staples Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 67% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	67.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the consumer staples sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $1.4 billion to $281.34 billion. As of October 31, 2024, the Fund had significant investments in consumer staples companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 40 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">1.4 billion to $281.34 billion. As of October 31, 2024, the Fund had significant investments in consumer </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">staples companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Consumer Staples Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Consumer Staples Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Consumer Staples AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.53%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter15.54%June 30, 2020Worst Quarter-19.62%March 31, 2020Year-to-Date9.53%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Consumer Staples AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Consumer Staples AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Consumer Staples AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Consumer Staples AlphaDEX Fund | Consumer Staples Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CONSUMER STAPLES COMPANIES RISK. Consumer staples companies provide products directly to the consumer that are typically considered non-discretionary items based on consumer purchasing habits. Such products include food, beverages, household items and tobacco. Companies providing these products may be affected by the regulation of various product components and production methods, new laws, regulations or litigation, marketing campaigns, competitive pricing and other factors affecting consumer demand. Changes in the worldwide economy, demographics, consumer preferences, consumer spending, exploration and production spending may adversely affect these companies, as well as natural and man-made disasters, political, social or labor unrest, world events and economic conditions.
First Trust Consumer Staples AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Consumer Staples AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Consumer Staples AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Consumer Staples AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Consumer Staples AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Consumer Staples AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Consumer Staples AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Consumer Staples AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Consumer Staples AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Consumer Staples AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Consumer Staples AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Consumer Staples AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Consumer Staples AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Consumer Staples AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Consumer Staples AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Consumer Staples AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Consumer Staples AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Consumer Staples AlphaDEX Fund | First Trust Consumer Staples AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.12%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.62%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.62%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 63
3 Years	rr_ExpenseExampleNoRedemptionYear03	199
5 Years	rr_ExpenseExampleNoRedemptionYear05	346
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 774
2014	rr_AnnualReturn2014	21.05%
2015	rr_AnnualReturn2015	6.14%
2016	rr_AnnualReturn2016	4.70%
2017	rr_AnnualReturn2017	7.81%
2018	rr_AnnualReturn2018	(11.40%)
2019	rr_AnnualReturn2019	20.72%
2020	rr_AnnualReturn2020	4.74%
2021	rr_AnnualReturn2021	21.68%
2022	rr_AnnualReturn2022	3.32%
2023	rr_AnnualReturn2023	1.92%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	9.53%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	15.54%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(19.62%)
1 Year	rr_AverageAnnualReturnYear01	1.92%
5 Years	rr_AverageAnnualReturnYear05	10.13%
10 Years	rr_AverageAnnualReturnYear10	7.61%
Since Inception	rr_AverageAnnualReturnSinceInception	8.73%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Consumer Staples AlphaDEX Fund | After tax on distributions | First Trust Consumer Staples AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.33%
5 Years	rr_AverageAnnualReturnYear05	9.41%
10 Years	rr_AverageAnnualReturnYear10	6.88%
Since Inception	rr_AverageAnnualReturnSinceInception	8.09%
First Trust Consumer Staples AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Consumer Staples AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.13%
5 Years	rr_AverageAnnualReturnYear05	7.68%
10 Years	rr_AverageAnnualReturnYear10	5.78%
Since Inception	rr_AverageAnnualReturnSinceInception	7.03%
First Trust Consumer Staples AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Consumer Staples AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Consumer Staples AlphaDEX Fund | StrataQuant® Consumer Staples Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.50%
5 Years	rr_AverageAnnualReturnYear05	10.79%
10 Years	rr_AverageAnnualReturnYear10	8.28%
Since Inception	rr_AverageAnnualReturnSinceInception	9.48%
First Trust Consumer Staples AlphaDEX Fund | S&P 500® Consumer Staples Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.52%
5 Years	rr_AverageAnnualReturnYear05	10.86%
10 Years	rr_AverageAnnualReturnYear10	8.54%
Since Inception	rr_AverageAnnualReturnSinceInception	9.23%
First Trust Consumer Staples AlphaDEX Fund | Russell 1000® Consumer Staples Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.59%)	[2]
5 Years	rr_AverageAnnualReturnYear05	9.65%	[2]
10 Years	rr_AverageAnnualReturnYear10	7.70%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Energy AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Energy AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Energy Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 60% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	60.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the energy sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $2.11 billion to $518.83 billion. As of October 31, 2024, the Fund had significant investments in energy companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 40 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.11 billion to $518.83 billion. As of October 31, 2024, the Fund had significant investments in energy </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">companies. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Energy Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. In addition to the implementation of the RGS, Russell combined the Russell 1000® Integrated Oils Index and the Russell 1000® Other Energy Index into one index, the Russell 1000® Energy Index. Consequently, performance data is not available for all the periods shown in the table for the Russell 1000® Energy Index because this index did not exist until on or about September 18, 2008.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Energy AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was -1.02%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter65.48%June 30, 2020Worst Quarter-61.97%March 31, 2020Year-to-Date-1.02%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Energy AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Energy AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Energy AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Energy AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Energy AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Energy AlphaDEX Fund | Energy Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	ENERGY COMPANIES RISK. The success of energy companies may be cyclical and highly dependent on energy prices. The market value of securities issued by energy companies may decline for many reasons, including, among other things, changes in the levels and volatility of global energy prices, energy supply and demand, capital expenditures on exploration and production of energy sources, exchange rates, interest rates, economic conditions, tax treatment, energy conservation efforts, increased competition and technological advances. Energy companies may be subject to substantial government regulation and contractual fixed pricing, which may increase the cost of doing business and limit the earnings of these companies. A significant portion of the revenues of energy companies may depend on a relatively small number of customers, including governmental entities and utilities. As a result, governmental budget constraints may have a material adverse effect on the stock prices of energy companies. Energy companies may also operate in, or engage in transactions involving, countries with less developed regulatory regimes or a history of expropriation, nationalization or other adverse policies. Energy companies also face a significant risk of liability from accidents resulting in injury or loss of life or property, pollution or other environmental problems, equipment malfunctions or mishandling of materials and a risk of loss from terrorism, political strife or natural disasters.
First Trust Energy AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Energy AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Energy AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Energy AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Energy AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Energy AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Energy AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Energy AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Energy AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Energy AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Energy AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Energy AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Energy AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Energy AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Energy AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Energy AlphaDEX Fund | First Trust Energy AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.11%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.61%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.61%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 62
3 Years	rr_ExpenseExampleNoRedemptionYear03	195
5 Years	rr_ExpenseExampleNoRedemptionYear05	340
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 762
2014	rr_AnnualReturn2014	(16.01%)
2015	rr_AnnualReturn2015	(32.38%)
2016	rr_AnnualReturn2016	20.46%
2017	rr_AnnualReturn2017	(5.12%)
2018	rr_AnnualReturn2018	(24.64%)
2019	rr_AnnualReturn2019	(6.84%)
2020	rr_AnnualReturn2020	(20.02%)
2021	rr_AnnualReturn2021	51.52%
2022	rr_AnnualReturn2022	47.14%
2023	rr_AnnualReturn2023	0.78%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(1.02%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	65.48%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(61.97%)
1 Year	rr_AverageAnnualReturnYear01	0.78%
5 Years	rr_AverageAnnualReturnYear05	10.86%
10 Years	rr_AverageAnnualReturnYear10	(1.98%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.44%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Energy AlphaDEX Fund | After tax on distributions | First Trust Energy AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(0.52%)
5 Years	rr_AverageAnnualReturnYear05	9.56%
10 Years	rr_AverageAnnualReturnYear10	(2.84%)
Since Inception	rr_AverageAnnualReturnSinceInception	(0.18%)
First Trust Energy AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Energy AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	0.42%
5 Years	rr_AverageAnnualReturnYear05	7.87%
10 Years	rr_AverageAnnualReturnYear10	(1.90%)
Since Inception	rr_AverageAnnualReturnSinceInception	0.03%
First Trust Energy AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Energy AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Energy AlphaDEX Fund | StrataQuant® Energy Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	1.51%
5 Years	rr_AverageAnnualReturnYear05	11.59%
10 Years	rr_AverageAnnualReturnYear10	(1.42%)
Since Inception	rr_AverageAnnualReturnSinceInception	1.07%
First Trust Energy AlphaDEX Fund | S&P 500® Energy Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.33%)
5 Years	rr_AverageAnnualReturnYear05	13.40%
10 Years	rr_AverageAnnualReturnYear10	3.48%
Since Inception	rr_AverageAnnualReturnSinceInception	4.58%
First Trust Energy AlphaDEX Fund | Russell 1000® Energy Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.33%)	[2]
5 Years	rr_AverageAnnualReturnYear05	12.87%	[2]
10 Years	rr_AverageAnnualReturnYear10	2.81%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Financials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Financials AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Financials Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 75% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	75.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the financials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 103 securities with a market capitalization range of $647.99 million to $972.07 billion. As of October 31, 2024, the Fund had significant investments in financial companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 103 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">647.99 million to $972.07 billion. As of October 31, 2024, the Fund had significant investments in </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">financial companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Financial Services Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Financial Services Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Financials AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 19.89%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter36.00%December 31, 2020Worst Quarter-36.22%March 31, 2020Year-to-Date19.89%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Financials AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Financials AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Financials AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Financials AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Financials AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Financials AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Financials AlphaDEX Fund | Financial Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.
First Trust Financials AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Financials AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Financials AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Financials AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Financials AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Financials AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Financials AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Financials AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Financials AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Financials AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Financials AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Financials AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Financials AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Financials AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Financials AlphaDEX Fund | First Trust Financials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.11%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.61%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.61%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 62
3 Years	rr_ExpenseExampleNoRedemptionYear03	195
5 Years	rr_ExpenseExampleNoRedemptionYear05	340
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 762
2014	rr_AnnualReturn2014	8.71%
2015	rr_AnnualReturn2015	1.21%
2016	rr_AnnualReturn2016	18.16%
2017	rr_AnnualReturn2017	17.92%
2018	rr_AnnualReturn2018	(11.63%)
2019	rr_AnnualReturn2019	26.26%
2020	rr_AnnualReturn2020	5.92%
2021	rr_AnnualReturn2021	37.59%
2022	rr_AnnualReturn2022	(9.17%)
2023	rr_AnnualReturn2023	9.22%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	19.89%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	36.00%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(36.22%)
1 Year	rr_AverageAnnualReturnYear01	9.22%
5 Years	rr_AverageAnnualReturnYear05	12.79%
10 Years	rr_AverageAnnualReturnYear10	9.48%
Since Inception	rr_AverageAnnualReturnSinceInception	6.85%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Financials AlphaDEX Fund | After tax on distributions | First Trust Financials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	7.77%
5 Years	rr_AverageAnnualReturnYear05	11.60%
10 Years	rr_AverageAnnualReturnYear10	8.50%
Since Inception	rr_AverageAnnualReturnSinceInception	6.02%
First Trust Financials AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Financials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	5.36%
5 Years	rr_AverageAnnualReturnYear05	9.60%
10 Years	rr_AverageAnnualReturnYear10	7.22%
Since Inception	rr_AverageAnnualReturnSinceInception	5.19%
First Trust Financials AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Financials AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Financials AlphaDEX Fund | StrataQuant® Financials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	9.90%
5 Years	rr_AverageAnnualReturnYear05	13.55%
10 Years	rr_AverageAnnualReturnYear10	10.21%
Since Inception	rr_AverageAnnualReturnSinceInception	7.68%
First Trust Financials AlphaDEX Fund | S&P 500® Financials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	12.15%
5 Years	rr_AverageAnnualReturnYear05	11.97%
10 Years	rr_AverageAnnualReturnYear10	10.05%
Since Inception	rr_AverageAnnualReturnSinceInception	3.42%
First Trust Financials AlphaDEX Fund | Russell 1000® Financials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.46%	[2]
5 Years	rr_AverageAnnualReturnYear05	14.78%	[2]
10 Years	rr_AverageAnnualReturnYear10	11.59%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Health Care AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Health Care AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Health Care Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 98% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	98.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the health care sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 78 securities with a market capitalization range of $1.94 billion to $746.2 billion. As of October 31, 2024, the Fund had significant investments in health care companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 78 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">1.94 billion to $746.2 billion. As of October 31, 2024, the Fund had significant investments in health </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">care companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Health Care Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Health Care Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Health Care AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.40%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter22.21%June 30, 2020Worst Quarter-19.65%December 31, 2018Year-to-Date8.40%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Health Care AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Health Care AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Health Care AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Health Care AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Health Care AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Health Care AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Health Care AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Health Care AlphaDEX Fund | Health Care Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	HEALTH CARE COMPANIES RISK. Health care companies, such as companies providing medical and healthcare goods and services, companies engaged in manufacturing medical equipment, supplies and pharmaceuticals, as well as operating health care facilities and the provision of managed health care, may be affected by government regulations and government health care programs, increases or decreases in the cost of medical products and services and product liability claims, among other factors. Many health care companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Health care companies are also subject to competitive forces that may result in price discounting, may be thinly capitalized and susceptible to product obsolescence.
First Trust Health Care AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Health Care AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Health Care AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Health Care AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Health Care AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Health Care AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Health Care AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Health Care AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Health Care AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Health Care AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Health Care AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Health Care AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Health Care AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Health Care AlphaDEX Fund | First Trust Health Care AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.60%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.60%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 61
3 Years	rr_ExpenseExampleNoRedemptionYear03	192
5 Years	rr_ExpenseExampleNoRedemptionYear05	335
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 750
2014	rr_AnnualReturn2014	25.40%
2015	rr_AnnualReturn2015	0.23%
2016	rr_AnnualReturn2016	(5.20%)
2017	rr_AnnualReturn2017	21.78%
2018	rr_AnnualReturn2018	(1.26%)
2019	rr_AnnualReturn2019	22.31%
2020	rr_AnnualReturn2020	27.85%
2021	rr_AnnualReturn2021	15.18%
2022	rr_AnnualReturn2022	(12.21%)
2023	rr_AnnualReturn2023	(4.50%)
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	8.40%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	22.21%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(19.65%)
1 Year	rr_AverageAnnualReturnYear01	(4.50%)
5 Years	rr_AverageAnnualReturnYear05	8.59%
10 Years	rr_AverageAnnualReturnYear10	8.02%
Since Inception	rr_AverageAnnualReturnSinceInception	10.46%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Health Care AlphaDEX Fund | After tax on distributions | First Trust Health Care AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.60%)
5 Years	rr_AverageAnnualReturnYear05	8.55%
10 Years	rr_AverageAnnualReturnYear10	8.00%
Since Inception	rr_AverageAnnualReturnSinceInception	10.43%
First Trust Health Care AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Health Care AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(2.67%)
5 Years	rr_AverageAnnualReturnYear05	6.77%
10 Years	rr_AverageAnnualReturnYear10	6.54%
Since Inception	rr_AverageAnnualReturnSinceInception	9.03%
First Trust Health Care AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Health Care AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Health Care AlphaDEX Fund | StrataQuant® Health Care Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(3.88%)
5 Years	rr_AverageAnnualReturnYear05	9.32%
10 Years	rr_AverageAnnualReturnYear10	8.73%
Since Inception	rr_AverageAnnualReturnSinceInception	11.23%
First Trust Health Care AlphaDEX Fund | S&P 500® Health Care Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.06%
5 Years	rr_AverageAnnualReturnYear05	11.59%
10 Years	rr_AverageAnnualReturnYear10	11.35%
Since Inception	rr_AverageAnnualReturnSinceInception	10.28%
First Trust Health Care AlphaDEX Fund | Russell 1000® Health Care Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	2.44%	[2]
5 Years	rr_AverageAnnualReturnYear05	11.51%	[2]
10 Years	rr_AverageAnnualReturnYear10	11.37%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

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Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Industrials-Producer Durables AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Industrials/Producer Durables AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Industrials Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 78% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	78.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the industrials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 138 securities with a market capitalization range of $1.78 billion to $190.26 billion. As of October 31, 2024, the Fund had significant investments in industrials companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 138 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">1.78 billion to $190.26 billion. As of October 31, 2024, the Fund had significant investments in </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">industrials companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Producer Durables Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Producer Durables Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Industrials/Producer Durables AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 17.53%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter24.70%June 30, 2020Worst Quarter-32.06%March 31, 2020Year-to-Date17.53%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Industrials-Producer Durables AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Industrials-Producer Durables AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Industrials-Producer Durables AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Industrials-Producer Durables AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Industrials-Producer Durables AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Industrials-Producer Durables AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Industrials-Producer Durables AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Industrials-Producer Durables AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Industrials-Producer Durables AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Industrials-Producer Durables AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Industrials-Producer Durables AlphaDEX Fund | Industrials Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.
First Trust Industrials-Producer Durables AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Industrials-Producer Durables AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Industrials-Producer Durables AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Industrials-Producer Durables AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Industrials-Producer Durables AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Industrials-Producer Durables AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Industrials-Producer Durables AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Industrials-Producer Durables AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Industrials-Producer Durables AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Industrials-Producer Durables AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Industrials-Producer Durables AlphaDEX Fund | First Trust Industrials-Producer Durables AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.60%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.60%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 61
3 Years	rr_ExpenseExampleNoRedemptionYear03	192
5 Years	rr_ExpenseExampleNoRedemptionYear05	335
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 750
2014	rr_AnnualReturn2014	8.13%
2015	rr_AnnualReturn2015	(13.44%)
2016	rr_AnnualReturn2016	26.76%
2017	rr_AnnualReturn2017	24.13%
2018	rr_AnnualReturn2018	(15.01%)
2019	rr_AnnualReturn2019	33.40%
2020	rr_AnnualReturn2020	12.63%
2021	rr_AnnualReturn2021	25.27%
2022	rr_AnnualReturn2022	(16.65%)
2023	rr_AnnualReturn2023	26.80%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	17.53%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	24.70%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(32.06%)
1 Year	rr_AverageAnnualReturnYear01	26.80%
5 Years	rr_AverageAnnualReturnYear05	14.74%
10 Years	rr_AverageAnnualReturnYear10	9.55%
Since Inception	rr_AverageAnnualReturnSinceInception	8.21%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Industrials-Producer Durables AlphaDEX Fund | After tax on distributions | First Trust Industrials-Producer Durables AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.37%
5 Years	rr_AverageAnnualReturnYear05	14.32%
10 Years	rr_AverageAnnualReturnYear10	9.16%
Since Inception	rr_AverageAnnualReturnSinceInception	7.86%
First Trust Industrials-Producer Durables AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Industrials-Producer Durables AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.85%
5 Years	rr_AverageAnnualReturnYear05	11.65%
10 Years	rr_AverageAnnualReturnYear10	7.63%
Since Inception	rr_AverageAnnualReturnSinceInception	6.73%
First Trust Industrials-Producer Durables AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Industrials-Producer Durables AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Industrials-Producer Durables AlphaDEX Fund | StrataQuant® Industrials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	27.67%
5 Years	rr_AverageAnnualReturnYear05	15.53%
10 Years	rr_AverageAnnualReturnYear10	10.29%
Since Inception	rr_AverageAnnualReturnSinceInception	8.98%
First Trust Industrials-Producer Durables AlphaDEX Fund | S&P 500® Industrials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	18.13%
5 Years	rr_AverageAnnualReturnYear05	14.21%
10 Years	rr_AverageAnnualReturnYear10	10.00%
Since Inception	rr_AverageAnnualReturnSinceInception	8.69%
First Trust Industrials-Producer Durables AlphaDEX Fund | Russell 1000® Industrials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.35%	[2]
5 Years	rr_AverageAnnualReturnYear05	12.16%	[2]
10 Years	rr_AverageAnnualReturnYear10	9.34%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Materials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Materials AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Materials Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	53.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the materials sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 36 securities with a market capitalization range of $2.71 billion to $217.81 billion. As of October 31, 2024, the Fund had significant investments in materials companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024.To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 36 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.71 billion to $217.81 billion. As of October 31, 2024, the Fund had significant investments in </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">materials companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Materials and Processing Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Materials and Processing Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Materials AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was -1.82%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter28.72%December 31, 2020Worst Quarter-31.31%March 31, 2020Year-to-Date-1.82%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Materials AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Materials AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Materials AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Materials AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Materials AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Materials AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Materials AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Materials AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Materials AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Materials AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Materials AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Materials AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Materials AlphaDEX Fund | Materials Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MATERIALS COMPANIES RISK. Materials and processing companies are involved in the extraction or processing of raw materials such as metals, ore and forestry products. These companies are sensitive to changes in the business cycle and fluctuations in the supply and demand for raw materials. Further, certain materials and processing companies can be affected by shifts in the housing market, as many produced raw materials are components of construction projects. Rising wage costs can also impact companies that rely on skilled labor. In addition, materials and processing companies may be significantly affected by volatility of commodity prices, import controls, worldwide competition, liability for environmental damage, depletion of resources and mandated expenditures for safety and pollution control devices.
First Trust Materials AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Materials AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Materials AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Materials AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Materials AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Materials AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Materials AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Materials AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Materials AlphaDEX Fund | First Trust Materials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.11%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.61%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.61%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 62
3 Years	rr_ExpenseExampleNoRedemptionYear03	195
5 Years	rr_ExpenseExampleNoRedemptionYear05	340
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 762
2014	rr_AnnualReturn2014	(0.98%)
2015	rr_AnnualReturn2015	(9.83%)
2016	rr_AnnualReturn2016	29.17%
2017	rr_AnnualReturn2017	23.68%
2018	rr_AnnualReturn2018	(22.55%)
2019	rr_AnnualReturn2019	21.54%
2020	rr_AnnualReturn2020	22.21%
2021	rr_AnnualReturn2021	30.88%
2022	rr_AnnualReturn2022	(0.80%)
2023	rr_AnnualReturn2023	16.10%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	(1.82%)
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.72%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(31.31%)
1 Year	rr_AverageAnnualReturnYear01	16.10%
5 Years	rr_AverageAnnualReturnYear05	17.49%
10 Years	rr_AverageAnnualReturnYear10	9.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.30%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Materials AlphaDEX Fund | After tax on distributions | First Trust Materials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.12%
5 Years	rr_AverageAnnualReturnYear05	16.68%
10 Years	rr_AverageAnnualReturnYear10	8.80%
Since Inception	rr_AverageAnnualReturnSinceInception	8.67%
First Trust Materials AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Materials AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	9.50%
5 Years	rr_AverageAnnualReturnYear05	13.75%
10 Years	rr_AverageAnnualReturnYear10	7.38%
Since Inception	rr_AverageAnnualReturnSinceInception	7.52%
First Trust Materials AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Materials AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Materials AlphaDEX Fund | StrataQuant® Materials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.80%
5 Years	rr_AverageAnnualReturnYear05	18.31%
10 Years	rr_AverageAnnualReturnYear10	10.22%
Since Inception	rr_AverageAnnualReturnSinceInception	10.09%
First Trust Materials AlphaDEX Fund | S&P 500® Materials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	12.55%
5 Years	rr_AverageAnnualReturnYear05	13.58%
10 Years	rr_AverageAnnualReturnYear10	8.60%
Since Inception	rr_AverageAnnualReturnSinceInception	7.11%
First Trust Materials AlphaDEX Fund | Russell 1000® Basic Materials Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.35%	[2]
5 Years	rr_AverageAnnualReturnYear05	14.02%	[2]
10 Years	rr_AverageAnnualReturnYear10	8.86%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Technology AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Technology AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Technology Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 119% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	119.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the technology sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 103 securities with a market capitalization range of $2.7 billion to $3.43 trillion. As of October 31, 2024, the Fund had significant investments in information technology companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 103 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.7 billion to $3.43 trillion. As of October 31, 2024, the Fund had significant investments in information </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">technology companies.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Technology Index , on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Technology Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Technology AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.19%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter40.67%June 30, 2020Worst Quarter-18.87%June 30, 2022Year-to-Date8.19%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Technology AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Technology AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Technology AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Technology AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Technology AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Technology AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Technology AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Technology AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Technology AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Technology AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Technology AlphaDEX Fund | Information Technology Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INFORMATION TECHNOLOGY COMPANIES RISK. Information technology companies produce and provide hardware, software and information technology systems and services. These companies may be adversely affected by rapidly changing technologies, short product life cycles, fierce competition, aggressive pricing and reduced profit margins, the loss of patent, copyright and trademark protections, cyclical market patterns, evolving industry standards and frequent new product introductions. In addition, information technology companies are particularly vulnerable to federal, state and local government regulation, and competition and consolidation, both domestically and internationally, including competition from foreign competitors with lower production costs. Information technology companies also heavily rely on intellectual property rights and may be adversely affected by the loss or impairment of those rights.
First Trust Technology AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Technology AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Technology AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Technology AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Technology AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Technology AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Technology AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Technology AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Technology AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Technology AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Technology AlphaDEX Fund | First Trust Technology AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.10%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.60%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.60%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 61
3 Years	rr_ExpenseExampleNoRedemptionYear03	192
5 Years	rr_ExpenseExampleNoRedemptionYear05	335
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 750
2014	rr_AnnualReturn2014	16.38%
2015	rr_AnnualReturn2015	(3.30%)
2016	rr_AnnualReturn2016	15.42%
2017	rr_AnnualReturn2017	35.80%
2018	rr_AnnualReturn2018	2.69%
2019	rr_AnnualReturn2019	38.79%
2020	rr_AnnualReturn2020	54.11%
2021	rr_AnnualReturn2021	18.26%
2022	rr_AnnualReturn2022	(30.40%)
2023	rr_AnnualReturn2023	40.43%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	8.19%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	40.67%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Jun. 30, 2022
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(18.87%)
1 Year	rr_AverageAnnualReturnYear01	40.43%
5 Years	rr_AverageAnnualReturnYear05	19.84%
10 Years	rr_AverageAnnualReturnYear10	16.17%
Since Inception	rr_AverageAnnualReturnSinceInception	12.13%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Technology AlphaDEX Fund | After tax on distributions | First Trust Technology AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	40.19%
5 Years	rr_AverageAnnualReturnYear05	19.71%
10 Years	rr_AverageAnnualReturnYear10	15.97%
Since Inception	rr_AverageAnnualReturnSinceInception	11.99%
First Trust Technology AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Technology AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	23.93%
5 Years	rr_AverageAnnualReturnYear05	16.16%
10 Years	rr_AverageAnnualReturnYear10	13.67%
Since Inception	rr_AverageAnnualReturnSinceInception	10.51%
First Trust Technology AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Technology AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Technology AlphaDEX Fund | StrataQuant® Technology Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	40.85%
5 Years	rr_AverageAnnualReturnYear05	20.55%
10 Years	rr_AverageAnnualReturnYear10	16.82%
Since Inception	rr_AverageAnnualReturnSinceInception	12.89%
First Trust Technology AlphaDEX Fund | S&P 500® Information Technology Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	57.84%
5 Years	rr_AverageAnnualReturnYear05	26.95%
10 Years	rr_AverageAnnualReturnYear10	20.79%
Since Inception	rr_AverageAnnualReturnSinceInception	15.48%
First Trust Technology AlphaDEX Fund | Russell 1000® Technology Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	66.89%	[2]
5 Years	rr_AverageAnnualReturnYear05	26.45%	[2]
10 Years	rr_AverageAnnualReturnYear10	20.26%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Utilities AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Utilities AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the StrataQuant® Utilities Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 53% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	53.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is part of the “StrataQuant® Series,” a family of custom enhanced indices developed, maintained and owned by ICE Data Indices, LLC or its affiliates (“IDI” or the “Index Provider”). The Index Provider reserves the right to, at any time, change the number of stocks comprising the Index by adding or deleting one or more stocks, or replacing one or more stocks contained in the Index with one or more substitute stocks of its choice, if in the Index Provider’s discretion, such addition, deletion or substitution is necessary or appropriate to maintain the quality and/or character of the Index. According to the Index Provider, the Index is a modified, equal-dollar weighted index designed to objectively identify and select stocks from the Russell 1000® Index in the utilities sector that have the potential for greater capital appreciation. The Index uses the AlphaDEX® selection methodology which aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Russell 1000® Index consists of approximately 1,000 of the largest stocks within the Russell 3000® Index. The Russell 3000® Index is constructed to represent approximately 98% of the investable U.S. equity market. According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Russell 1000® Index that meet the Index Provider’s share class and liquidity screens. 2.The stocks in the selection universe are ranked on both growth and value factors. Each stock is classified as either a value stock, a growth stock or a combination of growth and value, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” A stock classified as a combination of growth and value will receive the better of the two scores. 3.The selection universe is then divided into respective sectors as defined by the Index Provider. The component stocks contained in the sector for which the Fund is named are ranked according to their selection score from step 2. 4.The number of “selected stocks” for the relevant sector will be the greater of the top 75% of securities from step 3 or 40 stocks. The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 40 securities with a market capitalization range of $3.27 billion to $162.97 billion. As of October 31, 2024, the Fund had significant investments in utilities companies. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;">The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 40 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">3.27 billion to $162.97 billion. As of October 31, 2024, the Fund had significant investments in utilities </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">companies. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.With respect to the Russell 1000® Utilities Index, on or about September 18, 2008, Russell Investment Group (“Russell”) began calculating its Russell U.S. Indices using an enhanced Russell sector scheme, the Russell Global Sectors (the “RGS”). The RGS and the former U.S. sector scheme ran in tandem until June 30, 2009, when Russell officially transitioned to the RGS and ceased calculating its indices using the U.S. sector scheme. Consequently, performance data is not available for the Russell 1000® Utilities Index for the “Since Inception” period set forth in the table because performance data does not exist using solely the U.S. sector scheme or alternatively, using solely the RGS.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Utilities AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 23.75%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter16.49%March 31, 2016Worst Quarter-15.50%March 31, 2020Year-to-Date23.75%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Utilities AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Utilities AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Utilities AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Utilities AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Utilities AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Utilities AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Utilities AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Utilities AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Utilities AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Utilities AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Utilities AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Utilities AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Utilities AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Utilities AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Utilities AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Utilities AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Utilities AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Utilities AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Utilities AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Utilities AlphaDEX Fund | Utility Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	UTILITY COMPANIES RISK. Utility companies include companies producing or providing gas, electricity or water. These companies are subject to the risk of the imposition of rate caps, increased competition due to deregulation, the difficulty in obtaining an adequate return on invested capital or in financing large construction projects counterparty risk, the limitations on operations and increased costs and delays attributable to environmental considerations and the capital market’s ability to absorb utility debt. In addition, taxes, government regulation, domestic and international politics, price and supply fluctuations, volatile interest rates and energy conservation may negatively affect utility companies.
First Trust Utilities AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Utilities AlphaDEX Fund | First Trust Utilities AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.13%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.63%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.63%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 64
3 Years	rr_ExpenseExampleNoRedemptionYear03	202
5 Years	rr_ExpenseExampleNoRedemptionYear05	351
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 787
2014	rr_AnnualReturn2014	25.49%
2015	rr_AnnualReturn2015	(6.43%)
2016	rr_AnnualReturn2016	22.52%
2017	rr_AnnualReturn2017	0.94%
2018	rr_AnnualReturn2018	5.60%
2019	rr_AnnualReturn2019	11.68%
2020	rr_AnnualReturn2020	1.25%
2021	rr_AnnualReturn2021	17.69%
2022	rr_AnnualReturn2022	3.74%
2023	rr_AnnualReturn2023	(2.20%)
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	23.75%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Mar. 31, 2016
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	16.49%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(15.50%)
1 Year	rr_AverageAnnualReturnYear01	(2.20%)
5 Years	rr_AverageAnnualReturnYear05	6.19%
10 Years	rr_AverageAnnualReturnYear10	7.55%
Since Inception	rr_AverageAnnualReturnSinceInception	5.91%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Utilities AlphaDEX Fund | After tax on distributions | First Trust Utilities AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(3.22%)
5 Years	rr_AverageAnnualReturnYear05	5.04%
10 Years	rr_AverageAnnualReturnYear10	6.29%
Since Inception	rr_AverageAnnualReturnSinceInception	4.67%
First Trust Utilities AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Utilities AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.32%)
5 Years	rr_AverageAnnualReturnYear05	4.29%
10 Years	rr_AverageAnnualReturnYear10	5.43%
Since Inception	rr_AverageAnnualReturnSinceInception	4.13%
First Trust Utilities AlphaDEX Fund | Russell 1000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.53%
5 Years	rr_AverageAnnualReturnYear05	15.52%
10 Years	rr_AverageAnnualReturnYear10	11.80%
Since Inception	rr_AverageAnnualReturnSinceInception	9.31%
First Trust Utilities AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Utilities AlphaDEX Fund | StrataQuant® Utilities Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(1.54%)
5 Years	rr_AverageAnnualReturnYear05	6.85%
10 Years	rr_AverageAnnualReturnYear10	8.27%
Since Inception	rr_AverageAnnualReturnSinceInception	6.72%
First Trust Utilities AlphaDEX Fund | S&P 500® Utilities Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(7.08%)
5 Years	rr_AverageAnnualReturnYear05	7.11%
10 Years	rr_AverageAnnualReturnYear10	8.91%
Since Inception	rr_AverageAnnualReturnSinceInception	6.35%
First Trust Utilities AlphaDEX Fund | Russell 1000® Utilities Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	(4.66%)	[2]
5 Years	rr_AverageAnnualReturnYear05	7.49%	[2]
10 Years	rr_AverageAnnualReturnYear10	7.67%	[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Large Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Large Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap CoreTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 88% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	88.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the 500 largest securities from the Nasdaq US BenchmarkTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 375 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 375 securities with a market capitalization range of $10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 375 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index and a broad-based market index.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Core Index to the Nasdaq AlphaDEX Large Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Core Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index</span><span style="font-family:Arial;font-size:9.00pt;">,</span><span style="font-family:Arial;font-size:9.00pt;line-height:10.80pt;"> </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index and a broad-based market index.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Large Cap Core AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 16.48%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter25.33%June 30, 2020Worst Quarter-26.64%March 31, 2020Year-to-Date16.48%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Large Cap Core AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Large Cap Core AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Large Cap Core AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Large Cap Core AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Large Cap Core AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Large Cap Core AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Large Cap Core AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Large Cap Core AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Large Cap Core AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Large Cap Core AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Large Cap Core AlphaDEX Fund | Large Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
First Trust Large Cap Core AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Large Cap Core AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Large Cap Core AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Large Cap Core AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Large Cap Core AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Large Cap Core AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Large Cap Core AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Large Cap Core AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Large Cap Core AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Large Cap Core AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Large Cap Core AlphaDEX Fund | First Trust Large Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.58%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.58%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 59
3 Years	rr_ExpenseExampleNoRedemptionYear03	186
5 Years	rr_ExpenseExampleNoRedemptionYear05	324
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 726
2014	rr_AnnualReturn2014	12.34%
2015	rr_AnnualReturn2015	(3.87%)
2016	rr_AnnualReturn2016	14.11%
2017	rr_AnnualReturn2017	21.52%
2018	rr_AnnualReturn2018	(9.80%)
2019	rr_AnnualReturn2019	27.02%
2020	rr_AnnualReturn2020	14.13%
2021	rr_AnnualReturn2021	26.78%
2022	rr_AnnualReturn2022	(11.92%)
2023	rr_AnnualReturn2023	14.40%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	16.48%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	25.33%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(26.64%)
1 Year	rr_AverageAnnualReturnYear01	14.40%
5 Years	rr_AverageAnnualReturnYear05	13.12%
10 Years	rr_AverageAnnualReturnYear10	9.60%
Since Inception	rr_AverageAnnualReturnSinceInception	8.18%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Large Cap Core AlphaDEX Fund | After tax on distributions | First Trust Large Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.72%
5 Years	rr_AverageAnnualReturnYear05	12.49%
10 Years	rr_AverageAnnualReturnYear10	9.00%
Since Inception	rr_AverageAnnualReturnSinceInception	7.64%
First Trust Large Cap Core AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Large Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.50%
5 Years	rr_AverageAnnualReturnYear05	10.18%
10 Years	rr_AverageAnnualReturnYear10	7.55%
Since Inception	rr_AverageAnnualReturnSinceInception	6.58%
First Trust Large Cap Core AlphaDEX Fund | Nasdaq AlphaDEX Large Cap Core(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.12%	[2]
5 Years	rr_AverageAnnualReturnYear05	13.82%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Core AlphaDEX Fund | Nasdaq US 500 Large Cap(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	27.14%	[2]
5 Years	rr_AverageAnnualReturnYear05	15.74%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Core AlphaDEX Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.29%
5 Years	rr_AverageAnnualReturnYear05	15.69%
10 Years	rr_AverageAnnualReturnYear10	12.03%
Since Inception	rr_AverageAnnualReturnSinceInception	9.33%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Large Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Large Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap GrowthTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 116% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	116.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 500 Large CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 187 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 187 securities with a market capitalization range of $10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrials companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 187 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">10.18 billion to $3.43 trillion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in industrials companies</span><span style="font-family:Arial;font-size:9.00pt;">, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Growth Index to the Nasdaq AlphaDEX Large Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Growth Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Large Cap Growth AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 20.10%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter28.17%June 30, 2020Worst Quarter-18.53%December 31, 2018Year-to-Date20.10%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Large Cap Growth AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Large Cap Growth AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Large Cap Growth AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Large Cap Growth AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Large Cap Growth AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Large Cap Growth AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Large Cap Growth AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Large Cap Growth AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Large Cap Growth AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Large Cap Growth AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Large Cap Growth AlphaDEX Fund | Industrials Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.
First Trust Large Cap Growth AlphaDEX Fund | Large Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
First Trust Large Cap Growth AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Large Cap Growth AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Large Cap Growth AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Large Cap Growth AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Large Cap Growth AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Large Cap Growth AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Large Cap Growth AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Large Cap Growth AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Large Cap Growth AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Large Cap Growth AlphaDEX Fund | First Trust Large Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.58%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.58%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 59
3 Years	rr_ExpenseExampleNoRedemptionYear03	186
5 Years	rr_ExpenseExampleNoRedemptionYear05	324
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 726
2014	rr_AnnualReturn2014	14.47%
2015	rr_AnnualReturn2015	4.29%
2016	rr_AnnualReturn2016	2.55%
2017	rr_AnnualReturn2017	25.18%
2018	rr_AnnualReturn2018	(5.98%)
2019	rr_AnnualReturn2019	28.34%
2020	rr_AnnualReturn2020	33.11%
2021	rr_AnnualReturn2021	24.40%
2022	rr_AnnualReturn2022	(22.98%)
2023	rr_AnnualReturn2023	20.12%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	20.10%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.17%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Dec. 31, 2018
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(18.53%)
1 Year	rr_AverageAnnualReturnYear01	20.12%
5 Years	rr_AverageAnnualReturnYear05	14.48%
10 Years	rr_AverageAnnualReturnYear10	10.98%
Since Inception	rr_AverageAnnualReturnSinceInception	8.74%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Large Cap Growth AlphaDEX Fund | After tax on distributions | First Trust Large Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.77%
5 Years	rr_AverageAnnualReturnYear05	14.21%
10 Years	rr_AverageAnnualReturnYear10	10.70%
Since Inception	rr_AverageAnnualReturnSinceInception	8.48%
First Trust Large Cap Growth AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Large Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.89%
5 Years	rr_AverageAnnualReturnYear05	11.51%
10 Years	rr_AverageAnnualReturnYear10	8.96%
Since Inception	rr_AverageAnnualReturnSinceInception	7.27%
First Trust Large Cap Growth AlphaDEX Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.29%
5 Years	rr_AverageAnnualReturnYear05	15.69%
10 Years	rr_AverageAnnualReturnYear10	12.03%
Since Inception	rr_AverageAnnualReturnSinceInception	9.33%
First Trust Large Cap Growth AlphaDEX Fund | Nasdaq AlphaDEX Large Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.90%	[2]
5 Years	rr_AverageAnnualReturnYear05	15.19%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Growth AlphaDEX Fund | Nasdaq US 500 Large Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	31.58%	[2]
5 Years	rr_AverageAnnualReturnYear05	17.47%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Growth AlphaDEX Fund | S&P 500® Growth Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	30.03%
5 Years	rr_AverageAnnualReturnYear05	16.23%
10 Years	rr_AverageAnnualReturnYear10	13.35%
Since Inception	rr_AverageAnnualReturnSinceInception	10.95%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Large Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Large Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Large Cap ValueTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 81% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	81.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 500 Large CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 187 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 187 securities with a market capitalization range of $10.68 billion to $518.83 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index.The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 187 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">10.68 billion to $518.83 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Large Cap Value Index to the Nasdaq AlphaDEX Large Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Large Cap Value Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Large Cap Value AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 13.21%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter23.83%June 30, 2020Worst Quarter-34.34%March 31, 2020Year-to-Date13.21%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Large Cap Value AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Large Cap Value AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Large Cap Value AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Large Cap Value AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Large Cap Value AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Large Cap Value AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Large Cap Value AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Large Cap Value AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Large Cap Value AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Large Cap Value AlphaDEX Fund | Large Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
First Trust Large Cap Value AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Large Cap Value AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Large Cap Value AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Large Cap Value AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Large Cap Value AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Large Cap Value AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Large Cap Value AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Large Cap Value AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Large Cap Value AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Large Cap Value AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Large Cap Value AlphaDEX Fund | First Trust Large Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.58%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.58%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 59
3 Years	rr_ExpenseExampleNoRedemptionYear03	186
5 Years	rr_ExpenseExampleNoRedemptionYear05	324
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 726
2014	rr_AnnualReturn2014	10.87%
2015	rr_AnnualReturn2015	(10.27%)
2016	rr_AnnualReturn2016	23.92%
2017	rr_AnnualReturn2017	18.45%
2018	rr_AnnualReturn2018	(13.57%)
2019	rr_AnnualReturn2019	24.87%
2020	rr_AnnualReturn2020	(0.56%)
2021	rr_AnnualReturn2021	29.21%
2022	rr_AnnualReturn2022	(3.76%)
2023	rr_AnnualReturn2023	10.14%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	13.21%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	23.83%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(34.34%)
1 Year	rr_AverageAnnualReturnYear01	10.14%
5 Years	rr_AverageAnnualReturnYear05	11.20%
10 Years	rr_AverageAnnualReturnYear10	7.94%
Since Inception	rr_AverageAnnualReturnSinceInception	7.27%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Large Cap Value AlphaDEX Fund | After tax on distributions | First Trust Large Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	9.16%
5 Years	rr_AverageAnnualReturnYear05	10.27%
10 Years	rr_AverageAnnualReturnYear10	7.06%
Since Inception	rr_AverageAnnualReturnSinceInception	6.48%
First Trust Large Cap Value AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Large Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	5.97%
5 Years	rr_AverageAnnualReturnYear05	8.44%
10 Years	rr_AverageAnnualReturnYear10	5.95%
Since Inception	rr_AverageAnnualReturnSinceInception	5.59%
First Trust Large Cap Value AlphaDEX Fund | S&P 500® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	26.29%
5 Years	rr_AverageAnnualReturnYear05	15.69%
10 Years	rr_AverageAnnualReturnYear10	12.03%
Since Inception	rr_AverageAnnualReturnSinceInception	9.33%
First Trust Large Cap Value AlphaDEX Fund | Nasdaq AlphaDEX Large Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.86%	[2]
5 Years	rr_AverageAnnualReturnYear05	11.91%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Value AlphaDEX Fund | Nasdaq US 500 Large Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.36%	[2]
5 Years	rr_AverageAnnualReturnYear05	13.66%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Large Cap Value AlphaDEX Fund | S&P 500® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	22.23%
5 Years	rr_AverageAnnualReturnYear05	14.11%
10 Years	rr_AverageAnnualReturnYear10	10.01%
Since Inception	rr_AverageAnnualReturnSinceInception	7.29%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Mid Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Mid Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap CoreTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 103% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	103.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the securities that are ranked 501 to 1100 by full company market capitalization from the Nasdaq US BenchmarkTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 450 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 450 securities with a market capitalization range of $2.11 billion to $27.07 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 450 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.11 billion to $27.07 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Core Index to the Nasdaq AlphaDEX Mid Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Core Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Mid Cap Core AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 13.09%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter29.56%June 30, 2020Worst Quarter-33.06%March 31, 2020Year-to-Date13.09%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Mid Cap Core AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Mid Cap Core AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Mid Cap Core AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Mid Cap Core AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Mid Cap Core AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Mid Cap Core AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Mid Cap Core AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Mid Cap Core AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Mid Cap Core AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Mid Cap Core AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Mid Cap Core AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Mid Cap Core AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Mid Cap Core AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Mid Cap Core AlphaDEX Fund | Mid Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Mid Cap Core AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Mid Cap Core AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Mid Cap Core AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Mid Cap Core AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Mid Cap Core AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Mid Cap Core AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Mid Cap Core AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Mid Cap Core AlphaDEX Fund | First Trust Mid Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.08%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.58%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.58%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 59
3 Years	rr_ExpenseExampleNoRedemptionYear03	186
5 Years	rr_ExpenseExampleNoRedemptionYear05	324
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 726
2014	rr_AnnualReturn2014	5.56%
2015	rr_AnnualReturn2015	(8.09%)
2016	rr_AnnualReturn2016	18.67%
2017	rr_AnnualReturn2017	17.61%
2018	rr_AnnualReturn2018	(11.10%)
2019	rr_AnnualReturn2019	26.86%
2020	rr_AnnualReturn2020	16.14%
2021	rr_AnnualReturn2021	25.03%
2022	rr_AnnualReturn2022	(13.75%)
2023	rr_AnnualReturn2023	20.43%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	13.09%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	29.56%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(33.06%)
1 Year	rr_AverageAnnualReturnYear01	20.43%
5 Years	rr_AverageAnnualReturnYear05	13.86%
10 Years	rr_AverageAnnualReturnYear10	8.70%
Since Inception	rr_AverageAnnualReturnSinceInception	8.77%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Mid Cap Core AlphaDEX Fund | After tax on distributions | First Trust Mid Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.84%
5 Years	rr_AverageAnnualReturnYear05	13.31%
10 Years	rr_AverageAnnualReturnYear10	8.22%
Since Inception	rr_AverageAnnualReturnSinceInception	8.37%
First Trust Mid Cap Core AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Mid Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	12.06%
5 Years	rr_AverageAnnualReturnYear05	10.84%
10 Years	rr_AverageAnnualReturnYear10	6.84%
Since Inception	rr_AverageAnnualReturnSinceInception	7.21%
First Trust Mid Cap Core AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Mid Cap Core AlphaDEX Fund | Nasdaq AlphaDEX Mid Cap Core(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	21.22%	[2]
5 Years	rr_AverageAnnualReturnYear05	14.60%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Mid Cap Core AlphaDEX Fund | Nasdaq US 600 Mid Cap(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.07%	[2]
5 Years	rr_AverageAnnualReturnYear05	11.81%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Mid Cap Core AlphaDEX Fund | S&P MidCap 400® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.44%
5 Years	rr_AverageAnnualReturnYear05	12.62%
10 Years	rr_AverageAnnualReturnYear10	9.27%
Since Inception	rr_AverageAnnualReturnSinceInception	8.74%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Mid Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Mid Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap GrowthTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 134% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	134.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 600 Mid CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 225 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 225 securities with a market capitalization range of $2.69 billion to $27.07 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 225 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.69 billion to $27.07 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in industrial companies, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Growth Index to the Nasdaq AlphaDEX Mid Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Growth Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Mid Cap Growth AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 17.44%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter29.17%June 30, 2020Worst Quarter-22.72%March 31, 2020Year-to-Date17.44%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Mid Cap Growth AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Mid Cap Growth AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Mid Cap Growth AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Mid Cap Growth AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Mid Cap Growth AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Mid Cap Growth AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Mid Cap Growth AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Mid Cap Growth AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Mid Cap Growth AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Mid Cap Growth AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Mid Cap Growth AlphaDEX Fund | Industrials Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.
First Trust Mid Cap Growth AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Mid Cap Growth AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Mid Cap Growth AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Mid Cap Growth AlphaDEX Fund | Mid Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Mid Cap Growth AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Mid Cap Growth AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Mid Cap Growth AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Mid Cap Growth AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Mid Cap Growth AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Mid Cap Growth AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Mid Cap Growth AlphaDEX Fund | First Trust Mid Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.70%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.70%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 72
3 Years	rr_ExpenseExampleNoRedemptionYear03	224
5 Years	rr_ExpenseExampleNoRedemptionYear05	390
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 871
2014	rr_AnnualReturn2014	4.98%
2015	rr_AnnualReturn2015	(1.20%)
2016	rr_AnnualReturn2016	9.42%
2017	rr_AnnualReturn2017	24.92%
2018	rr_AnnualReturn2018	(7.36%)
2019	rr_AnnualReturn2019	32.57%
2020	rr_AnnualReturn2020	36.90%
2021	rr_AnnualReturn2021	13.38%
2022	rr_AnnualReturn2022	(23.82%)
2023	rr_AnnualReturn2023	21.06%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	17.44%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	29.17%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(22.72%)
1 Year	rr_AverageAnnualReturnYear01	21.06%
5 Years	rr_AverageAnnualReturnYear05	13.67%
10 Years	rr_AverageAnnualReturnYear10	9.56%
Since Inception	rr_AverageAnnualReturnSinceInception	10.35%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 19, 2011
First Trust Mid Cap Growth AlphaDEX Fund | After tax on distributions | First Trust Mid Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.93%
5 Years	rr_AverageAnnualReturnYear05	13.57%
10 Years	rr_AverageAnnualReturnYear10	9.44%
Since Inception	rr_AverageAnnualReturnSinceInception	10.23%
First Trust Mid Cap Growth AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Mid Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	12.46%
5 Years	rr_AverageAnnualReturnYear05	10.93%
10 Years	rr_AverageAnnualReturnYear10	7.81%
Since Inception	rr_AverageAnnualReturnSinceInception	8.66%
First Trust Mid Cap Growth AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	12.41%
First Trust Mid Cap Growth AlphaDEX Fund | Nasdaq AlphaDEX Mid Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	21.93%	[1]
5 Years	rr_AverageAnnualReturnYear05	14.52%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Mid Cap Growth AlphaDEX Fund | Nasdaq US 600 Mid Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.09%	[1]
5 Years	rr_AverageAnnualReturnYear05	11.04%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Mid Cap Growth AlphaDEX Fund | S&P MidCap 400® Growth Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.49%
5 Years	rr_AverageAnnualReturnYear05	11.91%
10 Years	rr_AverageAnnualReturnYear10	9.04%
Since Inception	rr_AverageAnnualReturnSinceInception	10.08%

[1] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Mid Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Mid Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Mid Cap ValueTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 98% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	98.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 600 Mid Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 600 Mid CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 225 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 225 securities with a market capitalization range of $2.11 billion to $19.57 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 225 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">2.11 billion to $19.57 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in </span><span style="font-family:Arial;font-size:9.00pt;">financial companies, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Mid Cap Value Index to the Nasdaq AlphaDEX Mid Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Mid Cap Value Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Mid Cap Value AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 8.14%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter31.25%June 30, 2020Worst Quarter-41.22%March 31, 2020Year-to-Date8.14%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Mid Cap Value AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Mid Cap Value AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Mid Cap Value AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Mid Cap Value AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Mid Cap Value AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Mid Cap Value AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Mid Cap Value AlphaDEX Fund | Financial Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.
First Trust Mid Cap Value AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Mid Cap Value AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Mid Cap Value AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Mid Cap Value AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Mid Cap Value AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Mid Cap Value AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Mid Cap Value AlphaDEX Fund | Mid Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MID CAPITALIZATION COMPANIES RISK. Mid capitalization companies may be more vulnerable to adverse general market or economic developments and thus may experience greater price volatility than more established large capitalization companies. Securities of mid capitalization companies may also be less liquid than securities of large capitalization companies and may have more limited trading volumes. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Mid Cap Value AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Mid Cap Value AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Mid Cap Value AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Mid Cap Value AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Mid Cap Value AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Mid Cap Value AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Mid Cap Value AlphaDEX Fund | First Trust Mid Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.70%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	none
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.70%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 72
3 Years	rr_ExpenseExampleNoRedemptionYear03	224
5 Years	rr_ExpenseExampleNoRedemptionYear05	390
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 871
2014	rr_AnnualReturn2014	5.57%
2015	rr_AnnualReturn2015	(13.11%)
2016	rr_AnnualReturn2016	26.29%
2017	rr_AnnualReturn2017	11.44%
2018	rr_AnnualReturn2018	(14.45%)
2019	rr_AnnualReturn2019	20.65%
2020	rr_AnnualReturn2020	0.94%
2021	rr_AnnualReturn2021	33.53%
2022	rr_AnnualReturn2022	(6.99%)
2023	rr_AnnualReturn2023	20.64%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	8.14%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	31.25%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(41.22%)
1 Year	rr_AverageAnnualReturnYear01	20.64%
5 Years	rr_AverageAnnualReturnYear05	12.78%
10 Years	rr_AverageAnnualReturnYear10	7.26%
Since Inception	rr_AverageAnnualReturnSinceInception	9.17%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 19, 2011
First Trust Mid Cap Value AlphaDEX Fund | After tax on distributions | First Trust Mid Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.71%
5 Years	rr_AverageAnnualReturnYear05	11.98%
10 Years	rr_AverageAnnualReturnYear10	6.56%
Since Inception	rr_AverageAnnualReturnSinceInception	8.53%
First Trust Mid Cap Value AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Mid Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	12.17%
5 Years	rr_AverageAnnualReturnYear05	9.80%
10 Years	rr_AverageAnnualReturnYear10	5.47%
Since Inception	rr_AverageAnnualReturnSinceInception	7.27%
First Trust Mid Cap Value AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	12.41%
First Trust Mid Cap Value AlphaDEX Fund | Nasdaq AlphaDEX Mid Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	21.64%	[1]
5 Years	rr_AverageAnnualReturnYear05	13.66%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Mid Cap Value AlphaDEX Fund | Nasdaq US 600 Mid Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	18.25%	[1]
5 Years	rr_AverageAnnualReturnYear05	11.50%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Mid Cap Value AlphaDEX Fund | S&P MidCap 400® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.39%
5 Years	rr_AverageAnnualReturnYear05	12.91%
10 Years	rr_AverageAnnualReturnYear10	9.17%
Since Inception	rr_AverageAnnualReturnSinceInception	10.36%

[1] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Multi Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Multi Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Multi Cap GrowthTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 115% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	115.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap GrowthTM Index, Nasdaq US 600 Mid Cap GrowthTM Index and Nasdaq US 700 Small Cap GrowthTM Index (the "Base Indices"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Indices are comprehensive, rules-based indices that include growth securities from the Nasdaq US 500 Large CapTM Index, Nasdaq US 600 Mid CapTM Index, and Nasdaq US 700 Small CapTM Index, respectively.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Indices. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. The following steps are performed for each size-segment independently: 3.The remaining stocks in each Base Index are then ranked on both growth and value factors within their respective Base Indices. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 187 stocks from the Nasdaq US 500 Large Cap GrowthTM Index, top 225 stocks from the Nasdaq US 600 Mid Cap GrowthTM Index and top 262 stocks from the Nasdaq US 700 Small Cap GrowthTM Index based on the selection score determined in step 3 comprise the “selected stocks.” Within each size-segment, the selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. 5.Using the quintile weights for each size-segment determined in Step 4, security weights are re-scaled such that the sum of large-cap security weights is 50%, the sum of medium-cap security weights is 30%, and the sum of small-cap security weights is 20%.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 674 securities with a market capitalization range of $631.42 million to $3.43 trillion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in industrials companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 674 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">631.42 million to $3.43 trillion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in industrials companies</span><span style="font-family:Arial;font-size:9.00pt;">, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Multi Cap Growth Index to the Nasdaq AlphaDEX Multi Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Multi Cap Growth Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Multi Cap Growth AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 19.19%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter28.87%June 30, 2020Worst Quarter-21.61%March 31, 2020Year-to-Date19.19%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Multi Cap Growth AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Multi Cap Growth AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Multi Cap Growth AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Multi Cap Growth AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Multi Cap Growth AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Multi Cap Growth AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Multi Cap Growth AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Multi Cap Growth AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Multi Cap Growth AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Multi Cap Growth AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Multi Cap Growth AlphaDEX Fund | Industrials Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDUSTRIALS COMPANIES RISK. Industrials companies convert unfinished goods into finished durables used to manufacture other goods or provide services. Examples of industrials companies include companies involved in the production of electrical equipment and components, industrial products, manufactured housing and telecommunications equipment, as well as defense and aerospace companies. General risks of industrials companies include the general state of the economy, exchange rates, commodity prices, intense competition, consolidation, domestic and international politics, government regulation, import controls, excess capacity, consumer demand and spending trends. In addition, industrials companies may also be significantly affected by overall capital spending levels, economic cycles, rapid technological changes, delays in modernization, labor relations, environmental liabilities, governmental and product liability and e-commerce initiatives.
First Trust Multi Cap Growth AlphaDEX Fund | Large Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
First Trust Multi Cap Growth AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Multi Cap Growth AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Multi Cap Growth AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Multi Cap Growth AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Multi Cap Growth AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Multi Cap Growth AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Multi Cap Growth AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Multi Cap Growth AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Multi Cap Growth AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Multi Cap Growth AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Multi Cap Growth AlphaDEX Fund | First Trust Multi Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.12%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.62%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.62%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 63
3 Years	rr_ExpenseExampleNoRedemptionYear03	199
5 Years	rr_ExpenseExampleNoRedemptionYear05	346
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 774
2014	rr_AnnualReturn2014	8.29%
2015	rr_AnnualReturn2015	2.10%
2016	rr_AnnualReturn2016	6.83%
2017	rr_AnnualReturn2017	24.68%
2018	rr_AnnualReturn2018	(6.22%)
2019	rr_AnnualReturn2019	27.17%
2020	rr_AnnualReturn2020	34.59%
2021	rr_AnnualReturn2021	20.71%
2022	rr_AnnualReturn2022	(23.77%)
2023	rr_AnnualReturn2023	19.22%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	19.19%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.87%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(21.61%)
1 Year	rr_AverageAnnualReturnYear01	19.22%
5 Years	rr_AverageAnnualReturnYear05	13.43%
10 Years	rr_AverageAnnualReturnYear10	10.00%
Since Inception	rr_AverageAnnualReturnSinceInception	8.67%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Multi Cap Growth AlphaDEX Fund | After tax on distributions | First Trust Multi Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	18.95%
5 Years	rr_AverageAnnualReturnYear05	13.23%
10 Years	rr_AverageAnnualReturnYear10	9.81%
Since Inception	rr_AverageAnnualReturnSinceInception	8.50%
First Trust Multi Cap Growth AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Multi Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	11.37%
5 Years	rr_AverageAnnualReturnYear05	10.67%
10 Years	rr_AverageAnnualReturnYear10	8.15%
Since Inception	rr_AverageAnnualReturnSinceInception	7.28%
First Trust Multi Cap Growth AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Multi Cap Growth AlphaDEX Fund | Nasdaq AlphaDEX Multi Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.04%	[2]
5 Years	rr_AverageAnnualReturnYear05	14.21%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Multi Cap Growth AlphaDEX Fund | Nasdaq US Multi Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	30.50%	[2]
5 Years	rr_AverageAnnualReturnYear05	16.75%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Multi Cap Growth AlphaDEX Fund | S&P Composite 1500® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	29.01%
5 Years	rr_AverageAnnualReturnYear05	15.85%
10 Years	rr_AverageAnnualReturnYear10	12.97%
Since Inception	rr_AverageAnnualReturnSinceInception	10.82%
First Trust Multi Cap Growth AlphaDEX Fund | S&P Composite 1500® Growth Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.47%
5 Years	rr_AverageAnnualReturnYear05	15.39%
10 Years	rr_AverageAnnualReturnYear10	11.76%
Since Inception	rr_AverageAnnualReturnSinceInception	9.30%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

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Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Multi Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Multi Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Multi Cap ValueTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 87% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	87.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 500 Large Cap ValueTM Index, Nasdaq US 600 Mid Cap ValueTM Index and Nasdaq US 700 Small Cap ValueTM Index (the "Base Indices"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Indices are comprehensive, rules-based indices that include value securities from the Nasdaq US 500 Large CapTM Index, Nasdaq US 600 Mid CapTM Index, and Nasdaq US 700 Small CapTM Index, respectively.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Indices. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. The following steps are performed for each size-segment independently: 3.The remaining stocks in each Base Index are then ranked on both growth and value factors within their respective Base Indices. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 187 stocks from the Nasdaq US 500 Large Cap ValueTM Index, top 225 stocks from the Nasdaq US 600 Mid Cap ValueTM Index and top 262 stocks from the Nasdaq US 700 Small Cap ValueTM Index based on the selection score determined in step 3 comprise the “selected stocks.” Within each size-segment, the selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index. 5.Using the quintile weights for each size-segment determined in Step 4, security weights are re-scaled such that the sum of large-cap security weights is 50%, the sum of medium-cap security weights is 30%, and the sum of small-cap security weights is 20%.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 674 securities with a market capitalization range of $755.28 million to $518.83 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 674 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">755.28 million to $518.83 billion. The securities of companies represented in the Index generally </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">Fund had significant investments in financial companies, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and three market indices.The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Multi Cap Value Index to the Nasdaq AlphaDEX Multi Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Multi Cap Value Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, a broad-based market index and </span><span style="font-family:Arial;font-size:9.00pt;">three market indices.</span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Multi Cap Value AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.69%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter28.70%June 30, 2020Worst Quarter-37.95%March 31, 2020Year-to-Date9.69%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Multi Cap Value AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Multi Cap Value AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Multi Cap Value AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Multi Cap Value AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Multi Cap Value AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Multi Cap Value AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Multi Cap Value AlphaDEX Fund | Financial Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.
First Trust Multi Cap Value AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Multi Cap Value AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Multi Cap Value AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Multi Cap Value AlphaDEX Fund | Large Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	LARGE CAPITALIZATION COMPANIES RISK. Large capitalization companies may grow at a slower rate and be less able to adapt to changing market conditions than smaller capitalization companies. Thus, the return on investment in securities of large capitalization companies may be less than the return on investment in securities of small and/or mid capitalization companies. The performance of large capitalization companies also tends to trail the overall market during different market cycles.
First Trust Multi Cap Value AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Multi Cap Value AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Multi Cap Value AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Multi Cap Value AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Multi Cap Value AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Multi Cap Value AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Multi Cap Value AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Multi Cap Value AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Multi Cap Value AlphaDEX Fund | Smaller Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALLER COMPANIES RISK. Small and/or mid capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than larger, more established companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than larger, more established companies.
First Trust Multi Cap Value AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Multi Cap Value AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Multi Cap Value AlphaDEX Fund | First Trust Multi Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1-rule]	rr_OtherExpensesOverAssets	0.14%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.64%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.64%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 65
3 Years	rr_ExpenseExampleNoRedemptionYear03	205
5 Years	rr_ExpenseExampleNoRedemptionYear05	357
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 798
2014	rr_AnnualReturn2014	7.86%
2015	rr_AnnualReturn2015	(12.45%)
2016	rr_AnnualReturn2016	25.85%
2017	rr_AnnualReturn2017	14.10%
2018	rr_AnnualReturn2018	(13.95%)
2019	rr_AnnualReturn2019	23.53%
2020	rr_AnnualReturn2020	2.28%
2021	rr_AnnualReturn2021	30.63%
2022	rr_AnnualReturn2022	(6.77%)
2023	rr_AnnualReturn2023	15.80%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	9.69%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	28.70%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(37.95%)
1 Year	rr_AverageAnnualReturnYear01	15.80%
5 Years	rr_AverageAnnualReturnYear05	12.25%
10 Years	rr_AverageAnnualReturnYear10	7.59%
Since Inception	rr_AverageAnnualReturnSinceInception	7.58%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Multi Cap Value AlphaDEX Fund | After tax on distributions | First Trust Multi Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.83%
5 Years	rr_AverageAnnualReturnYear05	11.42%
10 Years	rr_AverageAnnualReturnYear10	6.84%
Since Inception	rr_AverageAnnualReturnSinceInception	6.91%
First Trust Multi Cap Value AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Multi Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	9.31%
5 Years	rr_AverageAnnualReturnYear05	9.35%
10 Years	rr_AverageAnnualReturnYear10	5.73%
Since Inception	rr_AverageAnnualReturnSinceInception	5.95%
First Trust Multi Cap Value AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Multi Cap Value AlphaDEX Fund | S&P Composite 1500® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.47%
5 Years	rr_AverageAnnualReturnYear05	15.39%
10 Years	rr_AverageAnnualReturnYear10	11.76%
Since Inception	rr_AverageAnnualReturnSinceInception	9.30%
First Trust Multi Cap Value AlphaDEX Fund | Nasdaq AlphaDEX Multi Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.65%	[2]
5 Years	rr_AverageAnnualReturnYear05	13.06%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Multi Cap Value AlphaDEX Fund | Nasdaq US Multi Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	20.01%	[2]
5 Years	rr_AverageAnnualReturnYear05	13.52%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Multi Cap Value AlphaDEX Fund | S&P Composite 1500® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	21.64%
5 Years	rr_AverageAnnualReturnYear05	13.98%
10 Years	rr_AverageAnnualReturnYear10	9.91%
Since Inception	rr_AverageAnnualReturnSinceInception	7.39%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Small Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Small Cap Core AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap CoreTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Fee Waiver or Reimbursement over Assets, Date of Termination	rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination	<span style="font-family:Arial;font-size:8.10pt;font-style:italic;">November 30, 2025</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 112% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	112.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small CapTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index designed to measure the performance of the securities that are ranked 1101 to 1800 by full company market capitalization from the Nasdaq US BenchmarkTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 525 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 525 securities with a market capitalization range of $631.42 million to $11.28 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index.The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors from time to time. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 525 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">631.42 million to $11.28 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index.</span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Core Index to the Nasdaq AlphaDEX Small Cap CoreTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Core Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Small Cap Core AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 9.83%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter33.21%December 31, 2020Worst Quarter-36.40%March 31, 2020Year-to-Date9.83%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Small Cap Core AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Small Cap Core AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Small Cap Core AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Small Cap Core AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Small Cap Core AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Small Cap Core AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Small Cap Core AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Small Cap Core AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Small Cap Core AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Small Cap Core AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Small Cap Core AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Small Cap Core AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Small Cap Core AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Small Cap Core AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Small Cap Core AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Small Cap Core AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Small Cap Core AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Small Cap Core AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Small Cap Core AlphaDEX Fund | Small Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.
First Trust Small Cap Core AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Small Cap Core AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Small Cap Core AlphaDEX Fund | First Trust Small Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.50%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1]	rr_OtherExpensesOverAssets	0.09%
Acquired Fund Fees and Expenses[ctag:span_t-indent1-rule]	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.61%
Fee Waiver and Expense Reimbursement[ctag:span_t-indent1-rule]	rr_FeeWaiverOrReimbursementOverAssets	none	[1]
Net Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_NetExpensesOverAssets	0.61%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 62
3 Years	rr_ExpenseExampleNoRedemptionYear03	195
5 Years	rr_ExpenseExampleNoRedemptionYear05	340
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 762
2014	rr_AnnualReturn2014	1.31%
2015	rr_AnnualReturn2015	(8.91%)
2016	rr_AnnualReturn2016	22.72%
2017	rr_AnnualReturn2017	14.45%
2018	rr_AnnualReturn2018	(10.26%)
2019	rr_AnnualReturn2019	21.04%
2020	rr_AnnualReturn2020	19.23%
2021	rr_AnnualReturn2021	27.48%
2022	rr_AnnualReturn2022	(18.39%)
2023	rr_AnnualReturn2023	18.12%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	9.83%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	33.21%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(36.40%)
1 Year	rr_AverageAnnualReturnYear01	18.12%
5 Years	rr_AverageAnnualReturnYear05	12.14%
10 Years	rr_AverageAnnualReturnYear10	7.51%
Since Inception	rr_AverageAnnualReturnSinceInception	7.72%
Inception Date	rr_AverageAnnualReturnInceptionDate	May 08, 2007
First Trust Small Cap Core AlphaDEX Fund | After tax on distributions | First Trust Small Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.48%
5 Years	rr_AverageAnnualReturnYear05	11.67%
10 Years	rr_AverageAnnualReturnYear10	7.10%
Since Inception	rr_AverageAnnualReturnSinceInception	7.40%
First Trust Small Cap Core AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Small Cap Core AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	10.70%
5 Years	rr_AverageAnnualReturnYear05	9.46%
10 Years	rr_AverageAnnualReturnYear10	5.87%
Since Inception	rr_AverageAnnualReturnSinceInception	6.32%
First Trust Small Cap Core AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	9.15%
First Trust Small Cap Core AlphaDEX Fund | Nasdaq AlphaDEX Small Cap Core(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	18.95%	[2]
5 Years	rr_AverageAnnualReturnYear05	12.92%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Small Cap Core AlphaDEX Fund | Nasdaq US 700 Small Cap(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	18.22%	[2]
5 Years	rr_AverageAnnualReturnYear05	11.23%	[2]
10 Years	rr_AverageAnnualReturnYear10		[2]
Since Inception	rr_AverageAnnualReturnSinceInception		[2]
First Trust Small Cap Core AlphaDEX Fund | S&P SmallCap 600® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.05%
5 Years	rr_AverageAnnualReturnYear05	11.03%
10 Years	rr_AverageAnnualReturnYear10	8.66%
Since Inception	rr_AverageAnnualReturnSinceInception	8.42%

[1] First Trust Advisors L.P., the Fund’s investment advisor, has agreed to waive fees and/or reimburse Fund expenses to the extent that the operating expenses of the Fund (excluding interest expense, brokerage commissions and other trading expenses, taxes and extraordinary expenses) exceed 0.70% of its average daily net assets (the “Expense Cap”) at least through November 30, 2025. The agreement may be terminated by the Trust, on behalf of the Fund, at any time and by the Fund’s investment advisor only after November 30, 2025 upon 60 days’ written notice.

[2] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Small Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Small Cap Growth AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap GrowthTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 141% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	141.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap GrowthTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes growth securities from the Nasdaq US 700 Small CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 262 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 262 securities with a market capitalization range of $631.42 million to $11.28 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in health care companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 262 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">631.42 million to $11.28 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in </span><span style="font-family:Arial;font-size:9.00pt;">health care companies, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Growth Index to the Nasdaq AlphaDEX Small Cap GrowthTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Growth Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, </span><span style="font-family:Arial;font-size:9.00pt;">the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Small Cap Growth AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 18.92%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter30.65%December 31, 2020Worst Quarter-29.82%March 31, 2020Year-to-Date18.92%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Small Cap Growth AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Small Cap Growth AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Small Cap Growth AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Small Cap Growth AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Small Cap Growth AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Small Cap Growth AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Small Cap Growth AlphaDEX Fund | Growth Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	GROWTH STOCKS INVESTMENT RISK. Stocks exhibiting growth characteristics tend to be more volatile than certain other types of stocks and their prices usually fluctuate more dramatically than the overall stock market. A stock with growth characteristics can have sharp price declines due to decreases in current or expected earnings and may lack dividend payments that can help cushion its share price during declining markets.
First Trust Small Cap Growth AlphaDEX Fund | Health Care Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	HEALTH CARE COMPANIES RISK. Health care companies, such as companies providing medical and healthcare goods and services, companies engaged in manufacturing medical equipment, supplies and pharmaceuticals, as well as operating health care facilities and the provision of managed health care, may be affected by government regulations and government health care programs, increases or decreases in the cost of medical products and services and product liability claims, among other factors. Many health care companies are heavily dependent on patent protection, and the expiration of a company’s patent may adversely affect that company’s profitability. Health care companies are also subject to competitive forces that may result in price discounting, may be thinly capitalized and susceptible to product obsolescence.
First Trust Small Cap Growth AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Small Cap Growth AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Small Cap Growth AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Small Cap Growth AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Small Cap Growth AlphaDEX Fund | Market Maker Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Small Cap Growth AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Small Cap Growth AlphaDEX Fund | Non Correlation Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Small Cap Growth AlphaDEX Fund | Operational Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Small Cap Growth AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Small Cap Growth AlphaDEX Fund | Portfolio Turnover Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Small Cap Growth AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Small Cap Growth AlphaDEX Fund | Small Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.
First Trust Small Cap Growth AlphaDEX Fund | Trading Issues Risk [Member]
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Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Small Cap Growth AlphaDEX Fund | First Trust Small Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.70%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1]	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses[ctag:span_t-indent1-rule]	rr_AcquiredFundFeesAndExpensesOverAssets	0.01%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.71%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 73
3 Years	rr_ExpenseExampleNoRedemptionYear03	227
5 Years	rr_ExpenseExampleNoRedemptionYear05	395
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 883
2014	rr_AnnualReturn2014	(1.65%)
2015	rr_AnnualReturn2015	1.78%
2016	rr_AnnualReturn2016	13.92%
2017	rr_AnnualReturn2017	23.19%
2018	rr_AnnualReturn2018	(5.60%)
2019	rr_AnnualReturn2019	16.80%
2020	rr_AnnualReturn2020	32.08%
2021	rr_AnnualReturn2021	21.75%
2022	rr_AnnualReturn2022	(25.75%)
2023	rr_AnnualReturn2023	14.15%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	18.92%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Dec. 31, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	30.65%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(29.82%)
1 Year	rr_AverageAnnualReturnYear01	14.15%
5 Years	rr_AverageAnnualReturnYear05	9.74%
10 Years	rr_AverageAnnualReturnYear10	7.76%
Since Inception	rr_AverageAnnualReturnSinceInception	9.65%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 19, 2011
First Trust Small Cap Growth AlphaDEX Fund | After tax on distributions | First Trust Small Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.86%
5 Years	rr_AverageAnnualReturnYear05	9.59%
10 Years	rr_AverageAnnualReturnYear10	7.65%
Since Inception	rr_AverageAnnualReturnSinceInception	9.55%
First Trust Small Cap Growth AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Small Cap Growth AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	8.37%
5 Years	rr_AverageAnnualReturnYear05	7.66%
10 Years	rr_AverageAnnualReturnYear10	6.27%
Since Inception	rr_AverageAnnualReturnSinceInception	8.05%
First Trust Small Cap Growth AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	12.41%
First Trust Small Cap Growth AlphaDEX Fund | Nasdaq AlphaDEX Small Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	15.01%	[1]
5 Years	rr_AverageAnnualReturnYear05	10.60%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Small Cap Growth AlphaDEX Fund | Nasdaq US 700 Small Cap Growth(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	19.54%	[1]
5 Years	rr_AverageAnnualReturnYear05	9.86%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Small Cap Growth AlphaDEX Fund | S&P SmallCap 600® Growth Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	17.10%
5 Years	rr_AverageAnnualReturnYear05	10.42%
10 Years	rr_AverageAnnualReturnYear10	8.96%
Since Inception	rr_AverageAnnualReturnSinceInception	10.89%

[1] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
First Trust Small Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Risk/Return [Heading]	rr_RiskReturnHeading	Summary Information
Objective [Heading]	rr_ObjectiveHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Investment Objective</span>
Objective, Primary [Text Block]	rr_ObjectivePrimaryTextBlock	The First Trust Small Cap Value AlphaDEX® Fund (the “Fund”) seeks investment results that correspond generally to the price and yield (before the Fund’s fees and expenses) of an equity index called the Nasdaq AlphaDEX Small Cap ValueTM Index (the “Index”).
Expense [Heading]	rr_ExpenseHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Fees and Expenses of the Fund</span>
Expense Narrative [Text Block]	rr_ExpenseNarrativeTextBlock	The following table describes the fees and expenses you may pay if you buy, hold and sell shares of the Fund. Investors may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the table and example below.
Shareholder Fees Caption [Text]	rr_ShareholderFeesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Shareholder Fees</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(fees paid directly from your investment)</span>
Operating Expenses Caption [Text]	rr_OperatingExpensesCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-weight:bold;">Annual Fund Operating Expenses</span> <br/><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(expenses that you pay each year as a percentage of the value of your investment)</span>
Portfolio Turnover [Heading]	rr_PortfolioTurnoverHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Portfolio Turnover</span>
Portfolio Turnover [Text Block]	rr_PortfolioTurnoverTextBlock	The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 114% of the average value of its portfolio.
Portfolio Turnover, Rate	rr_PortfolioTurnoverRate	114.00%
Expense Example [Heading]	rr_ExpenseExampleHeading	<span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;font-weight:bold;">Example</span>
Expense Example, No Redemption Narrative [Text Block]	rr_ExpenseExampleNoRedemptionNarrativeTextBlock	The example below is intended to help you compare the cost of investing in the Fund with the cost of investing in other funds.The example assumes that you invest $10,000 in the Fund for the time periods indicated and then hold or sell all of your shares at the end of those periods. The example also assumes that your investment has a 5% return each year and that the Fund’s operating expenses remain at current levels. Although your actual costs may be higher or lower, based on these assumptions your costs would be:
Strategy [Heading]	rr_StrategyHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Investment Strategies</span>
Strategy Narrative [Text Block]	rr_StrategyNarrativeTextBlock	The Fund will normally invest at least 90% of its net assets (including investment borrowings) in the securities that comprise the Index. The Fund, using an “indexing” investment approach, attempts to replicate, before fees and expenses, the performance of the Index. The Index is owned and is developed, maintained and sponsored by Nasdaq, Inc. (the “Index Provider”). The Index Provider may, from time to time, exercise reasonable discretion as it deems appropriate in order to maintain Index integrity. According to the Index Provider, the Index employs the AlphaDEX® security selection methodology to select and weight securities from the Nasdaq US 700 Small Cap ValueTM Index (the "Base Index"). The AlphaDEX® security selection methodology aims to select securities that may generate positive alpha, or risk-adjusted returns, relative to traditional indices. Alpha is an indication of how much an investment outperforms or underperforms on a risk-adjusted basis relative to its benchmark. The Base Index is a comprehensive, rules-based index that includes value securities from the Nasdaq US 700 Small CapTM Index.According to the Index Provider, security selection for the Index will be conducted in the following manner: 1.The selection universe for the Index begins with all stocks in the Base Index. 2.The Index Provider then removes any duplicate (multiple share classes) stocks and stocks which do not meet the Index Provider’s liquidity screens. 3.The remaining stocks in the universe are then ranked on both growth and value factors. Each stock is classified as either a value stock or a growth stock, as determined by the Index Provider. A stock classified as a value stock will receive its value rank as its “selection score” and a stock classified as a growth stock will receive its growth rank as its “selection score.” 4.The top 262 stocks based on the selection score determined in step 3 comprise the “selected stocks.” The selected stocks are then split into quintiles based on their selection score, with higher scoring quintiles receiving a greater weight in the Index.The Index is reconstituted and rebalanced quarterly and the Fund will make corresponding changes to its portfolio shortly after the Index changes are made public. The Index’s quarterly rebalance and reconstitution schedule may cause the Fund to experience a higher rate of portfolio turnover. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. As of October 31, 2024, the Index was composed of 262 securities with a market capitalization range of $755.28 million to $5.3 billion. The securities of companies represented in the Index generally have market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, 2024, the Fund had significant investments in financial companies, although this may change from time to time. The Fund's investments will change as the Index changes and, as a result, the Fund may have significant investments in jurisdictions or investment sectors that it may not have had as of October 31, 2024. To the extent the Fund invests a significant portion of its assets in a given jurisdiction or investment sector, the Fund may be exposed to the risks associated with that jurisdiction or investment sector.
Strategy Portfolio Concentration [Text]	rr_StrategyPortfolioConcentration	<span style="font-family:Arial;font-size:9.00pt;"> The Fund will be concentrated in an industry or a group of industries to the </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">extent that the Index is so concentrated. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Index was composed of 262 securities with a market </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">capitalization range of $</span><span style="font-family:Arial;font-size:9.00pt;">755.28 million to $5.3 billion. The securities of companies represented in the Index generally have </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">market capitalizations that are consistent with the name of the Index. However, the Fund will not sell a security because the security has exceeded or fallen below the current market capitalization range of the Index. As of October 31, </span><span style="font-family:Arial;font-size:9.00pt;">2024, the Fund </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">had significant investments in financial companies, although this may change from time to time. </span>
Risk [Heading]	rr_RiskHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Principal Risks</span>
Risk Caption	rr_RiskCaption	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">You could lose money by investing in the Fund.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">An investment in the Fund is not a deposit of a bank and is not insured or </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;"> There can be no assurance that </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">the Fund’s investment objective will be achieved. The order of the below risk factors does not indicate the significance of any </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">particular risk factor.</span>
Bar Chart and Performance Table [Heading]	rr_BarChartAndPerformanceTableHeading	<span style="color:#000000;font-family:Arial;font-size:9.90pt;font-weight:bold;">Annual Total Return</span>
Performance Narrative [Text Block]	rr_PerformanceNarrativeTextBlock	The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. The Fund’s performance information is accessible on the Fund’s website at http://www.ftportfolios.com.On April 8, 2016, the Fund’s underlying index changed from the Defined Small Cap Value Index to the Nasdaq AlphaDEX Small Cap ValueTM Index. Therefore, the Fund’s performance and total returns shown below are not necessarily indicative of the performance that the Fund, based on its current Index, would have generated. Returns for an underlying index are only disclosed for those periods in which the index was in existence for the whole period. Because the Fund’s new underlying index had an inception date of January 11, 2016, it was not in existence for any of the periods disclosed. The new Index is substantially similar to the Defined Small Cap Value Index.
Performance Information Illustrates Variability of Returns [Text]	rr_PerformanceInformationIllustratesVariabilityOfReturns	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">The bar chart and table below illustrate the annual calendar year returns of the Fund based on net asset value as well as the average annual Fund and Index returns. The bar chart and table provide an indication of the risks of investing in the Fund by showing changes in the Fund’s performance from year-to-year and by showing how the Fund’s average annual total returns based on net asset value compared to those of the Index, the Base Index, a broad-based market index and a market index. </span>
Performance Availability Website Address [Text]	rr_PerformanceAvailabilityWebSiteAddress	<span style="font-family:Arial;font-size:9.00pt;">http://www.ftportfolios.com</span>
Performance Past Does Not Indicate Future [Text]	rr_PerformancePastDoesNotIndicateFuture	<span style="color:#000000;font-family:Arial;font-size:9.00pt;">The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.</span>
Bar Chart [Heading]	rr_BarChartHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">First Trust Small Cap Value AlphaDEX</span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">®</span><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;"> Fund</span> <br/><span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Calendar Year Total Returns as of 12/31 </span><span style="font-family:Arial;font-size:7pt;font-weight:bold;position:relative;top:-3.25pt;">(1)</span>
Bar Chart Footnotes [Text Block]	rr_BarChartFootnotesTextBlock	(1)The Fund's calendar year-to-date total return based on net asset value for the period 12/31/23 to 09/30/24 was 3.23%.
Bar Chart Closing [Text Block]	rr_BarChartClosingTextBlock	During the periods shown in the chart above:ReturnPeriod EndedBest Quarter36.65%June 30, 2020Worst Quarter-41.79%March 31, 2020Year-to-Date3.23%September 30, 2024
Performance Table Heading	rr_PerformanceTableHeading	<span style="font-family:Arial;font-size:9.90pt;font-weight:bold;">Average Annual Total Returns for the Periods Ended December 31, 2023</span>
Performance Table Uses Highest Federal Rate	rr_PerformanceTableUsesHighestFederalRate	<span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.</span>
Performance Table Not Relevant to Tax Deferred	rr_PerformanceTableNotRelevantToTaxDeferred	<span style="color:#000000;font-family:Arial;font-size:9.00pt;margin-left:0%;">Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts </span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">(</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;font-style:italic;">IRAs</span><span style="color:#000000;font-family:Arial;font-size:9.00pt;">) or employee-sponsored retirement plans.</span>
Performance Table Explanation after Tax Higher	rr_PerformanceTableExplanationAfterTaxHigher	<span style="font-family:Arial;font-size:9.00pt;">Returns after taxes on distributions reflect the taxed return on the payment of dividends </span><span style="font-family:Arial;font-size:9.00pt;margin-left:0%;">and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for </span><span style="font-family:Arial;font-size:9.00pt;">an index do not include expenses, which are deducted from Fund returns, or taxes.</span>
Performance Table Narrative	rr_PerformanceTableNarrativeTextBlock	The Fund’s past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.All after-tax returns are calculated using the historical highest individual federal marginal income tax rates and do not reflect the impact of any state or local tax.Returns after taxes on distributions reflect the taxed return on the payment of dividends and capital gains. Returns after taxes on distributions and sale of shares assume you sold your shares at period end, and, therefore, are also adjusted for any capital gains or losses incurred. Returns for an index do not include expenses, which are deducted from Fund returns, or taxes.Your own actual after-tax returns will depend on your specific tax situation and may differ from what is shown here. After-tax returns are not relevant to investors who hold Fund shares in tax-deferred accounts such as individual retirement accounts (IRAs) or employee-sponsored retirement plans.
First Trust Small Cap Value AlphaDEX Fund | Risk Lose Money [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	You could lose money by investing in the Fund.
First Trust Small Cap Value AlphaDEX Fund | Risk Not Insured Depository Institution [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	An investment in the Fund is not a deposit of a bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.
First Trust Small Cap Value AlphaDEX Fund | Authorized Participant Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	AUTHORIZED PARTICIPANT CONCENTRATION RISK. Only an authorized participant may engage in creation or redemption transactions directly with the Fund. A limited number of institutions act as authorized participants for the Fund. To the extent that these institutions exit the business or are unable to proceed with creation and/or redemption orders and no other authorized participant steps forward to create or redeem, the Fund’s shares may trade at a premium or discount (the difference between the market price of the Fund's shares and the Fund's net asset value) and possibly face delisting and the bid/ask spread (the difference between the price that someone is willing to pay for shares of the Fund at a specific point in time versus the price at which someone is willing to sell) on the Fund’s shares may widen.
First Trust Small Cap Value AlphaDEX Fund | Current Market Conditions Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CURRENT MARKET CONDITIONS RISK. Current market conditions risk is the risk that a particular investment, or shares of the Fund in general, may fall in value due to current market conditions. As a means to fight inflation, which remains at elevated levels, the Federal Reserve and certain foreign central banks have raised interest rates; however, the Federal Reserve has recently lowered interest rates and may continue to do so. U.S. regulators have proposed several changes to market and issuer regulations which would directly impact the Fund, and any regulatory changes could adversely impact the Fund’s ability to achieve its investment strategies or make certain investments. Recent and potential future bank failures could result in disruption to the broader banking industry or markets generally and reduce confidence in financial institutions and the economy as a whole, which may also heighten market volatility and reduce liquidity. Additionally, challenges in commercial real estate markets, including rising interest rates, declining valuations and increasing vacancies, could have a broader impact on financial markets. The ongoing adversarial political climate in the United States, as well as political and diplomatic events both domestic and abroad, have and may continue to have an adverse impact the U.S. regulatory landscape, markets and investor behavior, which could have a negative impact on the Fund’s investments and operations. The change in administration resulting from the 2024 United States national elections could result in significant impacts to international trade relations, tax and immigration policies, and other aspects of the national and international political and financial landscape, which could affect, among other things, inflation and the securities markets generally. Other unexpected political, regulatory and diplomatic events within the U.S. and abroad may affect investor and consumer confidence and may adversely impact financial markets and the broader economy. For example, ongoing armed conflicts between Russia and Ukraine in Europe and among Israel, Iran, Hamas and other militant groups in the Middle East, have caused and could continue to cause significant market disruptions and volatility within the markets in Russia, Europe, the Middle East and the United States. The hostilities and sanctions resulting from those hostilities have and could continue to have a significant impact on certain Fund investments as well as Fund performance and liquidity. The economies of the United States and its trading partners, as well as the financial markets generally, may be adversely impacted by trade disputes and other matters. For example, the United States has imposed trade barriers and restrictions on China. In addition, the Chinese government is engaged in a longstanding dispute with Taiwan, continually threatening an invasion. If the political climate between the United States and China does not improve or continues to deteriorate, if China were to attempt invading Taiwan, or if other geopolitical conflicts develop or worsen, economies, markets and individual securities may be adversely affected, and the value of the Fund’s assets may go down. A public health crisis and the ensuing policies enacted by governments and central banks may cause significant volatility and uncertainty in global financial markets, negatively impacting global growth prospects. As the COVID-19 global pandemic illustrated, such events may affect certain geographic regions, countries, sectors and industries more significantly than others. Advancements in technology may also adversely impact markets and the overall performance of the Fund. For instance, the economy may be significantly impacted by the advanced development and increased regulation of artificial intelligence. Additionally, cyber security breaches of both government and non-government entities could have negative impacts on infrastructure and the ability of such entities, including the Fund, to operate properly. These events, and any other future events, may adversely affect the prices and liquidity of the Fund’s portfolio investments and could result in disruptions in the trading markets.
First Trust Small Cap Value AlphaDEX Fund | Cyber Security Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	CYBER SECURITY RISK. The Fund is susceptible to operational risks through breaches in cyber security. A breach in cyber security refers to both intentional and unintentional events that may cause the Fund to lose proprietary information, suffer data corruption or lose operational capacity. Such events could cause the Fund to incur regulatory penalties, reputational damage, additional compliance costs associated with corrective measures and/or financial loss. Cyber security breaches may involve unauthorized access to the Fund’s digital information systems through “hacking” or malicious software coding but may also result from outside attacks such as denial-of-service attacks through efforts to make network services unavailable to intended users. In addition, cyber security breaches of the issuers of securities in which the Fund invests or the Fund’s third-party service providers, such as its administrator, transfer agent, custodian, or sub-advisor, as applicable, can also subject the Fund to many of the same risks associated with direct cyber security breaches. Although the Fund has established risk management systems designed to reduce the risks associated with cyber security, there is no guarantee that such efforts will succeed, especially because the Fund does not directly control the cyber security systems of issuers or third-party service providers.
First Trust Small Cap Value AlphaDEX Fund | Equity Securities Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	EQUITY SECURITIES RISK. The value of the Fund’s shares will fluctuate with changes in the value of the equity securities in which it invests. Equity securities prices fluctuate for several reasons, including changes in investors’ perceptions of the financial condition of an issuer or the general condition of the relevant equity market, such as market volatility, or when political or economic events affecting an issuer occur. Common stock prices may be particularly sensitive to rising interest rates, as the cost of capital rises and borrowing costs increase. Equity securities may decline significantly in price over short or extended periods of time, and such declines may occur in the equity market as a whole, or they may occur in only a particular country, company, industry or sector of the market.
First Trust Small Cap Value AlphaDEX Fund | Financial Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	FINANCIAL COMPANIES RISK. Financial companies, such as retail and commercial banks, insurance companies and financial services companies, are especially subject to the adverse effects of economic recession, currency exchange rates, extensive government regulation, decreases in the availability of capital, volatile interest rates, portfolio concentrations in geographic markets, industries or products (such as commercial and residential real estate loans), competition from new entrants and blurred distinctions in their fields of business.
First Trust Small Cap Value AlphaDEX Fund | Index Concentration Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX CONCENTRATION RISK. The Fund will be concentrated in an industry or a group of industries to the extent that the Index is so concentrated. To the extent that the Fund invests a significant percentage of its assets in a single asset class or the securities of issuers within the same country, state, region, industry or sector, an adverse economic, business or political development may affect the value of the Fund’s investments more than if the Fund were more broadly diversified. A significant exposure makes the Fund more susceptible to any single occurrence and may subject the Fund to greater market risk than a fund that is more broadly diversified. There may be instances in which the Index, for a variety of reasons including changes in the prices of individual securities held by the Fund, has a larger exposure to a small number of stocks or a single stock relative to the rest of the stocks in the Index. Under such circumstances, the Fund will not deviate from the Index except in rare circumstances or in an immaterial way and therefore the Fund’s returns would be more greatly influenced by the returns of the stock(s) with the larger exposure.
First Trust Small Cap Value AlphaDEX Fund | Index Or Model Constituent Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX OR MODEL CONSTITUENT RISK. The Fund may be a constituent of one or more indices or ETF models. As a result, the Fund may be included in one or more index-tracking exchange-traded funds or mutual funds. Being a component security of such a vehicle could greatly affect the trading activity involving the Fund’s shares, the size of the Fund and the market volatility of the Fund. Inclusion in an index could increase demand for the Fund and removal from an index could result in outsized selling activity in a relatively short period of time. As a result, the Fund’s net asset value could be negatively impacted and the Fund’s market price may be below the Fund’s net asset value during certain periods. In addition, index rebalances may potentially result in increased trading activity in the Fund's shares.
First Trust Small Cap Value AlphaDEX Fund | Index Provider Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	INDEX PROVIDER RISK. There is no assurance that the Index Provider, or any agents that act on its behalf, will compile the Index accurately, or that the Index will be determined, maintained, constructed, reconstituted, rebalanced, composed, calculated or disseminated accurately. The Index Provider and its agents do not provide any representation or warranty in relation to the quality, accuracy or completeness of data in the Index, and do not guarantee that the Index will be calculated in accordance with its stated methodology. The Advisor’s mandate as described in this prospectus is to manage the Fund consistently with the Index provided by the Index Provider. The Advisor relies upon the Index provider and its agents to accurately compile, maintain, construct, reconstitute, rebalance, compose, calculate and disseminate the Index accurately. Therefore, losses or costs associated with any Index Provider or agent errors generally will be borne by the Fund and its shareholders. To correct any such error, the Index Provider or its agents may carry out an unscheduled rebalance of the Index or other modification of Index constituents or weightings. When the Fund in turn rebalances its portfolio, any transaction costs and market exposure arising from such portfolio rebalancing will be borne by the Fund and its shareholders. Unscheduled rebalances also expose the Fund to additional tracking error risk. Errors in respect of the quality, accuracy and completeness of the data used to compile the Index may occur from time to time and may not be identified and corrected by the Index Provider for a period of time or at all, particularly where the Index is less commonly used as a benchmark by funds or advisors. For example, during a period where the Index contains incorrect constituents, the Fund tracking the Index would have market exposure to such constituents and would be underexposed to the Index’s other constituents. Such errors may negatively impact the Fund and its shareholders. The Index Provider and its agents rely on various sources of information to assess the criteria of issuers included in the Index, including information that may be based on assumptions and estimates. Neither the Fund nor the Advisor can offer assurances that the Index’s calculation methodology or sources of information will provide an accurate assessment of included issuers. Unusual market conditions or issuer-specific events may cause the Index Provider to postpone a scheduled rebalance, exclude or substitute a security in the Index or undertake other measures which could cause the Index to vary from its normal or expected composition. The postponement of a scheduled rebalance in a time of market volatility could mean that constituents that would otherwise be removed at rebalance due to changes in market capitalizations, issuer credit ratings, or other reasons may remain, causing the performance and constituents of the Index to vary from those expected under normal conditions. Apart from scheduled rebalances, the Index Provider or its agents may carry out additional ad hoc rebalances to the Index due to unusual market conditions or in order, for example, to correct an error in the selection of index constituents.
First Trust Small Cap Value AlphaDEX Fund | Market Capitalization Deviation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET CAPITALIZATION DEVIATION RISK. There can be no assurance that the securities held by the Fund will stay within the Fund’s intended market capitalization range. As a result, the Fund may be exposed to additional risk or investors may not be given the opportunity to invest fully in a certain market capitalization range.
First Trust Small Cap Value AlphaDEX Fund | Market Maker Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET MAKER RISK. The Fund faces numerous market trading risks, including the potential lack of an active market for Fund shares due to a limited number of market markers. Decisions by market makers or authorized participants to reduce their role or step away from these activities in times of market stress could inhibit the effectiveness of the arbitrage process in maintaining the relationship between the underlying values of the Fund’s portfolio securities and the Fund’s market price. The Fund may rely on a small number of third-party market makers to provide a market for the purchase and sale of shares. Any trading halt or other problem relating to the trading activity of these market makers could result in a dramatic change in the spread between the Fund’s net asset value and the price at which the Fund’s shares are trading on the Exchange, which could result in a decrease in value of the Fund’s shares. This reduced effectiveness could result in Fund shares trading at a discount to net asset value and also in greater than normal intraday bid-ask spreads for Fund shares.
First Trust Small Cap Value AlphaDEX Fund | Market Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	MARKET RISK. Market risk is the risk that a particular investment, or shares of the Fund in general, may fall in value. Securities are subject to market fluctuations caused by real or perceived adverse economic, political, and regulatory factors or market developments, changes in interest rates and perceived trends in securities prices. Shares of the Fund could decline in value or underperform other investments. In addition, local, regional or global events such as war, acts of terrorism, market manipulation, government defaults, government shutdowns, regulatory actions, political changes, diplomatic developments, the imposition of sanctions and other similar measures, spread of infectious diseases or other public health issues, recessions, natural disasters, or other events could have a significant negative impact on the Fund and its investments. Any of such circumstances could have a materially negative impact on the value of the Fund’s shares, the liquidity of an investment, and may result in increased market volatility. During any such events, the Fund’s shares may trade at increased premiums or discounts to their net asset value, the bid/ask spread on the Fund’s shares may widen and the returns on investment may fluctuate.
First Trust Small Cap Value AlphaDEX Fund | Non Correlation Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	NON-CORRELATION RISK. The Fund’s return may not match the return of the Index for a number of reasons. The Fund incurs operating expenses not applicable to the Index, and may incur costs in buying and selling securities, especially when rebalancing the Fund’s portfolio holdings to reflect changes in the composition of the Index. In addition, the Fund’s portfolio holdings may not exactly replicate the securities included in the Index or the ratios between the securities included in the Index. Additionally, in order to comply with its investment strategies and policies, the Fund portfolio may deviate from the composition of the Index. Accordingly, the Fund's return may underperform the return of the Index.
First Trust Small Cap Value AlphaDEX Fund | Operational Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	OPERATIONAL RISK. The Fund is subject to risks arising from various operational factors, including, but not limited to, human error, processing and communication errors, errors of the Fund’s service providers, counterparties or other third-parties, failed or inadequate processes and technology or systems failures. The Fund relies on third-parties for a range of services, including custody. Any delay or failure relating to engaging or maintaining such service providers may affect the Fund’s ability to meet its investment objective. Although the Fund and the Fund's investment advisor seek to reduce these operational risks through controls and procedures, there is no way to completely protect against such risks.
First Trust Small Cap Value AlphaDEX Fund | Passive Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PASSIVE INVESTMENT RISK. The Fund is not actively managed. The Fund invests in securities included in or representative of the Index regardless of investment merit. The Fund generally will not attempt to take defensive positions in declining markets. In the event that the Index is no longer calculated, the Index license is terminated or the identity or character of the Index is materially changed, the Fund will seek to engage a replacement index.
First Trust Small Cap Value AlphaDEX Fund | Portfolio Turnover Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PORTFOLIO TURNOVER RISK. High portfolio turnover may result in the Fund paying higher levels of transaction costs and may generate greater tax liabilities for shareholders. Portfolio turnover risk may cause the Fund’s performance to be less than expected.
First Trust Small Cap Value AlphaDEX Fund | Premium Discount Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	PREMIUM/DISCOUNT RISK. The market price of the Fund’s shares will generally fluctuate in accordance with changes in the Fund’s net asset value as well as the relative supply of and demand for shares on the Exchange. The Fund’s investment advisor cannot predict whether shares will trade below, at or above their net asset value because the shares trade on the Exchange at market prices and not at net asset value. Price differences may be due, in large part, to the fact that supply and demand forces at work in the secondary trading market for shares will be closely related, but not identical, to the same forces influencing the prices of the holdings of the Fund trading individually or in the aggregate at any point in time. However, given that shares can only be purchased and redeemed in Creation Units, and only to and from broker-dealers and large institutional investors that have entered into participation agreements (unlike shares of closed-end funds, which frequently trade at appreciable discounts from, and sometimes at premiums to, their net asset value), the Fund’s investment advisor believes that large discounts or premiums to the net asset value of shares should not be sustained. During stressed market conditions, the market for the Fund’s shares may become less liquid in response to deteriorating liquidity in the market for the Fund’s underlying portfolio holdings, which could in turn lead to differences between the market price of the Fund’s shares and their net asset value and the bid/ask spread on the Fund’s shares may widen.
First Trust Small Cap Value AlphaDEX Fund | Small Capitalization Companies Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	SMALL CAPITALIZATION COMPANIES RISK. Small capitalization companies may be more vulnerable to adverse general market or economic developments, and their securities may be less liquid and may experience greater price volatility than large and mid capitalization companies as a result of several factors, including limited trading volumes, fewer products or financial resources, management inexperience and less publicly available information. Accordingly, such companies are generally subject to greater market risk than large and mid capitalization companies.
First Trust Small Cap Value AlphaDEX Fund | Trading Issues Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	TRADING ISSUES RISK. Trading in Fund shares on the Exchange may be halted due to market conditions or for reasons that, in the view of the Exchange, make trading in shares inadvisable. In addition, trading in Fund shares on the Exchange is subject to trading halts caused by extraordinary market volatility pursuant to the Exchange’s “circuit breaker” rules. There can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund will continue to be met or will remain unchanged. The Fund may have difficulty maintaining its listing on the Exchange in the event the Fund’s assets are small, the Fund does not have enough shareholders, or if the Fund is unable to proceed with creation and/or redemption orders.
First Trust Small Cap Value AlphaDEX Fund | Value Stocks Investment Risk [Member]
Risk Return Abstract	rr_RiskReturnAbstract
Risk [Text Block]	rr_RiskTextBlock	VALUE STOCKS INVESTMENT RISK. The intrinsic value of a stock with value characteristics may not be fully recognized by the market for a long time or a stock judged to be undervalued may actually be appropriately priced at a low level.
First Trust Small Cap Value AlphaDEX Fund | First Trust Small Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price)[ctag:span_t-rule1]	rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice	none
Management Fees[ctag:span_t-indent1]	rr_ManagementFeesOverAssets	0.70%
Distribution and Service (12b-1) Fees[ctag:span_t-indent1]	rr_DistributionAndService12b1FeesOverAssets	none
Other Expenses[ctag:span_t-indent1]	rr_OtherExpensesOverAssets	none
Acquired Fund Fees and Expenses[ctag:span_t-indent1-rule]	rr_AcquiredFundFeesAndExpensesOverAssets	0.02%
Total Annual Fund Operating Expenses[ctag:span_t-indent1-rule3]	rr_ExpensesOverAssets	0.72%
1 Year	rr_ExpenseExampleNoRedemptionYear01	$ 74
3 Years	rr_ExpenseExampleNoRedemptionYear03	230
5 Years	rr_ExpenseExampleNoRedemptionYear05	401
10 Years	rr_ExpenseExampleNoRedemptionYear10	$ 894
2014	rr_AnnualReturn2014	3.76%
2015	rr_AnnualReturn2015	(16.67%)
2016	rr_AnnualReturn2016	30.15%
2017	rr_AnnualReturn2017	7.34%
2018	rr_AnnualReturn2018	(14.51%)
2019	rr_AnnualReturn2019	24.79%
2020	rr_AnnualReturn2020	10.00%
2021	rr_AnnualReturn2021	29.53%
2022	rr_AnnualReturn2022	(14.02%)
2023	rr_AnnualReturn2023	22.91%
Year to Date Return, Label	rr_YearToDateReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Year-to-Date</span>
Bar Chart, Year to Date Return, Date	rr_BarChartYearToDateReturnDate	Sep. 30, 2024
Bar Chart, Year to Date Return	rr_BarChartYearToDateReturn	3.23%
Highest Quarterly Return, Label	rr_HighestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Best Quarter</span>
Highest Quarterly Return, Date	rr_BarChartHighestQuarterlyReturnDate	Jun. 30, 2020
Highest Quarterly Return	rr_BarChartHighestQuarterlyReturn	36.65%
Lowest Quarterly Return, Label	rr_LowestQuarterlyReturnLabel	<span style="font-family:Arial;font-size:9.00pt;margin-left:0.0pt;">Worst Quarter</span>
Lowest Quarterly Return, Date	rr_BarChartLowestQuarterlyReturnDate	Mar. 31, 2020
Lowest Quarterly Return	rr_BarChartLowestQuarterlyReturn	(41.79%)
1 Year	rr_AverageAnnualReturnYear01	22.91%
5 Years	rr_AverageAnnualReturnYear05	13.45%
10 Years	rr_AverageAnnualReturnYear10	6.85%
Since Inception	rr_AverageAnnualReturnSinceInception	9.48%
Inception Date	rr_AverageAnnualReturnInceptionDate	Apr. 19, 2011
First Trust Small Cap Value AlphaDEX Fund | After tax on distributions | First Trust Small Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	22.08%
5 Years	rr_AverageAnnualReturnYear05	12.80%
10 Years	rr_AverageAnnualReturnYear10	6.29%
Since Inception	rr_AverageAnnualReturnSinceInception	8.96%
First Trust Small Cap Value AlphaDEX Fund | After tax on distributions and sale of fund shares | First Trust Small Cap Value AlphaDEX Fund
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	13.51%
5 Years	rr_AverageAnnualReturnYear05	10.44%
10 Years	rr_AverageAnnualReturnYear10	5.21%
Since Inception	rr_AverageAnnualReturnSinceInception	7.63%
First Trust Small Cap Value AlphaDEX Fund | Russell 3000® Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	25.96%
5 Years	rr_AverageAnnualReturnYear05	15.16%
10 Years	rr_AverageAnnualReturnYear10	11.48%
Since Inception	rr_AverageAnnualReturnSinceInception	12.41%
First Trust Small Cap Value AlphaDEX Fund | Nasdaq AlphaDEX Small Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	23.96%	[1]
5 Years	rr_AverageAnnualReturnYear05	14.36%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Small Cap Value AlphaDEX Fund | Nasdaq US 700 Small Cap Value(TM) Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	16.96%	[1]
5 Years	rr_AverageAnnualReturnYear05	12.27%	[1]
10 Years	rr_AverageAnnualReturnYear10		[1]
Since Inception	rr_AverageAnnualReturnSinceInception		[1]
First Trust Small Cap Value AlphaDEX Fund | S&P SmallCap 600® Value Index (reflects no deduction for fees, expenses or taxes)
Risk Return Abstract	rr_RiskReturnAbstract
1 Year	rr_AverageAnnualReturnYear01	14.89%
5 Years	rr_AverageAnnualReturnYear05	11.31%
10 Years	rr_AverageAnnualReturnYear10	8.17%
Since Inception	rr_AverageAnnualReturnSinceInception	10.31%

[1] Performance data is not available for all the periods shown in the table for the index because performance data does not exist for some of the entire periods.

XML

Label	Element	Value
Risk Return Abstract	rr_RiskReturnAbstract
Registrant Name	dei_EntityRegistrantName	First Trust Exchange-Traded AlphaDEX ® Fund
Prospectus Date	rr_ProspectusDate	Dec. 02, 2024
Document Creation Date	dei_DocumentCreationDate	Nov. 27, 2024